This is going to be a whiny, self-pitying post. Just to warn you.
The question is sometimes asked, "Why are stupid people frequently so much happier than intelligent people?" There are several reasons, including the deep awareness that many intelligent people have of the world's agonized suffering and ultimate meaninglessness, the painful empathy and sensitivity that are, disproportionately, the burden of the intelligent, the terrible tendency of intelligence to be self-conscious and self-critical, and the much more pronounced individuality of so many who are cursed with intelligence, which can make it harder for them to spontaneously bond with others in the way that stupid people can. But one important answer to the question is simply that the word overflows with stupidity, and it's frustrating and alienating to have to constantly deal with it, to have (in some respects) contempt for and to see through most things and people. As I wrote once, "Everywhere I turn, I'm suffocated by this miasma of stupidity." To be suffocated makes you unhappy.
A couple months ago I wrote an article about lesser-evil voting, in which I argued that leftists in swing states should vote for Biden. It seems to me that nothing could be more obvious—if, that is, you care about what happens to people. (Maybe a lot of leftists really don't care about that and are more interested in feeling "pure," by not voting at all or voting for a third party despite living in a swing state). Predictably, some readers were appalled. I corresponded with a couple of them for several days, calmly and logically answering their objections, but I was met only with sophistries and irrationality. As so often, reason failed to change any minds. And that's a quite disturbing thing, to one who values reason. It's as if you're telling someone (in the language of logicians), "if p, then q," and they agree; then you say, "p, therefore q," and they disagree. And they're unaware of the contradiction. All you can do is either laugh or cry.
To be so blind to reason, so unmotivated by rational considerations, strikes me as almost impossible; and yet the condition appears widespread. In the end, after a lifetime of observation, I've been forced to conclude that most people, including most educated people and intellectuals, are, to a greater or lesser degree, just bad at logical thinking. They're brilliant at emotional, value-laden thinking but bad at objective, logical thinking. You want to scream at them, "How can you not see this?! It's right in front of your eyes!," but they stare at you blankly and dimly and you know it wouldn't make a difference, so you give up and walk away.
Most people think mainly in terms of values. They know what they like and what they don't like—what people they like, ideas they like, beliefs and norms they like (or don't like)—and they won't let mere evidence or logic get in the way of their likes and dislikes. Again, I've written about this phenomenon elsewhere and won't go into any depth here. You can say it manifests a kind of stupidity, but what it manifests more fundamentally, I think, is just a lack of interest in logic and evidence. (The lack of interest may be closely related to a lack of ability, i.e. "stupidity" in the strict sense.) You can see the lack of interest when you're discussing some political question with someone and you make a series of arguments none of which they can satisfactorily answer, so in the end they say something like "Whatever, I know I'm right, this is all liberal bullshit." They're hardly disturbed at all by being confronted with arguments and evidence they can't respond to; they just shrug it off, conclude with an ad hoc ad hominem ("liberal, communist, socialist, Democrat!"—or, if your disagreement is with a feminist, "sexist, misogynist, mansplainer, cis white male!"—or, if you're disagreeing with a leftist committed to identity politics rather than class politics, "racist, class reductionist!," etc.), and go about their day without being intellectually disturbed in the slightest, secure in their beliefs notwithstanding contrary evidence and powerful arguments.
Such a lack of interest in reason—a lack of intellectual integrity—seems to predominate in every social category I can think of, whether young or old, poor or rich, educated or uneducated, left or (especially) right, etc. Only a very few people are highly sensitive, in all matters, to rational considerations. That is to say, only a few people are self-effacing enough to be overwhelmingly open-minded, perpetually willing and able to revise opinions, interested in truth more than anything else.
I sometimes wonder how Noam Chomsky, the epitome of an obsessively rational person, has been able to maintain his sanity in a world where everyone is dumber and more irrational than him. (Also infinitely less knowledgeable.) Here he is grappling with the intense stupidity—and nihilism—of postmodernism, for example.
I, and probably you, could list for a dozen paragraphs widespread examples of stupidity. Like, belief in Donald Trump's virtue and competence. Global warming denial. "Birtherism" regarding Obama. Creationism. 9/11 conspiracy theories. The belief that corporate pop music (Beyoncé, Taylor Swift, and the like) is high-quality music. Honking of car horns in a traffic jam. Recent calls to remove statues of Abraham Lincoln. Anti-materialistic idealism, an incredibly common thing in academia, the media, and popular thought and discourse. The equation of the Soviet Union with socialism or communism. Left-wing sectarianism. Right-wing...everything. (Racism, homophobia, nationalism, xenophobia, "libertarianism," infantile rhetorical slogans, etc.) Denials of biology's influence on gender. Love of Ayn Rand. Most comments under news articles and YouTube videos. The belief that the Russian Revolution has anything substantial to teach 21st-century revolutionaries. A large proportion of op-eds in the country's major newspapers. Bureaucratic inflexibility in trivial contexts where it serves no purpose except to harm someone. Male and female lack of self-understanding. Condemnation of Chomsky for his principled commitment to free speech. (In fact, nearly all other condemnations of Chomsky too.) Most shows on TV and nearly every commercial you'll ever see. Etc.
Moreover, little of this touches on another, even worse epidemic: the global pandemic of cruelty and assholishness, whether from political figures, employers, and bureaucrats (corporate or government) or in daily personal and internet interactions.
Here's a rather subtle example of stupidity: the common belief among social scientists that the social sciences have real intellectual substance. This is yet another point on which I agree with Chomsky. (Indeed, one of the reasons I was first drawn to Chomsky is that he validated my disdain for intellectuals' pretentiousness.) Frequently when I read some argument in sociology or history or political science or whatever, I'm struck by the pretentiousness of how an utterly simple idea is presented as if it is profound or controversial or genuinely substantive. The game annoys me, frankly. My Facebook feed regularly provides examples. For instance, I'm friends with a Marxist sociologist. One of his recent status updates was the following:
You can only have the view below if you don’t see social structure as simply reducible to people's locations in a class structure, but also something that encompasses political and ideological structures that set limits upon people’s practices. Erik Olin Wright was sharp on this:
"Class struggle, which is itself structurally limited and selected by various social structures, simultaneously reshapes those structures. The word 'simultaneously' is important in this formulation: social structures do not first limit and select class struggle, after which class struggle transforms those structures. Class struggle is intrinsically a process of transformation of structures, and thus the very process which sets limits on class struggle is at the same time transformed by the struggles so limited."
Ugh, the pretentiousness. What the first paragraph, written by my Facebook friend, means, in effect, is very simple: people are influenced and constrained not only by economic institutions but also by political and ideological institutions. Duh. The second paragraph, written by the reliably pretentious (and therefore celebrated) Erik Olin Wright, states a similarly obvious truth: conflict between classes is both shaped by and shapes a variety of institutions. Wow! What sharp dialectical thinking! What keen insight!
Not to pick on this Facebook friend of mine, but I was also edified to see, in another of his posts, this abstract of a paper he had published:
Capitalist social relations impose underlying constraints and developmental dynamics that lay down structural scope conditions on the dynamics we observe in seemingly noneconomic forms of inequality. But, and this is crucial, other processes unfold within the constraints of that dynamic endogeneity that in turn shape it...
Considering capitalism at a lower level of abstraction than Marx conceived in Capital entails understanding how society is organized at the level of the nation-state and amongst other things, examining national institutions, social policies and welfare states, patterns of racial formation, the conditions for social reproduction and gender inequality, immigration politics and the flow of migratory movements, and how a society's institutions are integrated with others globally. The upshot of our view is that each of these areas occurs in relative autonomy to the basic dynamics of capitalism but is nonetheless constrained by its developmental dynamism.
Such intellectual fireworks! Let's forgive the bad writing; it's practically a professional requirement for a sociologist. What does all that verbiage amount to? It's all about dialectics again, you see, and is therefore profound and revolutionary. What our esteemed sociologist is saying is that capitalism shapes inequalities like race and gender, even as the latter also shape capitalism! That's the crucial part! Thus, things like immigration politics, racial formation, and social policies are somewhat independent of capitalist processes but are also somewhat dependent on them! Surely you see how important and original this very sophisticated insight is.
What's stupid is that such pretentiousness, such high-school thinking jargonized to look sophisticated, is taken very seriously. People discuss it, debate it, publish it, make appreciative remarks about it—the scores of comments under the Facebook post were highly appreciative—and appear to believe that what they're discussing has some deep intellectual content. Meanwhile, I observe the charade and can't help thinking, "These people are just performing for each other."
(If you want to know what real intellectual content looks like, pick up a book on physics or linguistics or astronomy, or even epistemology or the philosophy of mind. I'm a historian and enjoy reading history, but I'm not deluded enough to think the discipline is of great intellectual interest.)
It often seems to me that I'm in a minority of one.
Sticking to the intellectual world, here's a very mild example of stupidity that irritates me: the tendency of writers across the political spectrum to write and speak in terms of culture, cultures, as if their favorite word, constantly repeated, is culture (also its conceptual relatives, such as discourse). All these people, including on the political left, are blissfully unaware that to emphasize culture(s) is itself an ideological act, not a display of objective thinking or intelligence or insight. For the very word "culture" tends to be idealist, obscurantist, obfuscatory, reifying, a distraction from the material and institutional realities of the economy, of governments, of the rule of a dominant class, coercive practices by which the majority are kept subordinate, in short the political economy of a given society. It's safer, for the rulers, to talk about these static things called "cultures" instead (Western culture, American culture, Islamic culture, the culture of poverty, the culture of the rich, cultural conflicts, culture wars, etc.). In the right context, it's fine to talk about culture; but the word's extreme overuse in academia is symptomatic—of academics' subordination to power. It's better to use the word society, which is less idealistic, less biased toward conservatism.
Here's another example, a subtle one, of how people who think of themselves as consummately objective and scientific are in fact locked in an ideological prison of the mind: the tendency—again, across the political spectrum—to speak of the Russian Revolution and the Soviet Union as if they had something to do with socialism or communism. E.g., I came across this sentence recently in a book on Antonio Gramsci: "The October revolution [of 1917] had demonstrated that a Communist takeover of power in a major European State was a real-world possibility; the rise and consolidation of fascism in Italy, on the other hand, showed that revolutionary dynamics in the postwar world by no means implied a linear outcome: the most spectacular political victory of the working class, confronted with its most humiliating defeat." No. The October coup—for that's what it was, a daring coup that was, admittedly, supported (generally after the fact) by large numbers of soldiers and workers—was a Bolshevik victory, not a working-class victory. For look at how it turned out: immediate suppression of workers' councils in factories, Leninist suppression of democracy, a horrific civil war against conservatives that decimated the country, smashing of working-class resistance to Bolshevism (e.g., in Kronstadt), the creation of a secret-police bureaucracy (the Cheka), and eventually the triumph of Stalinism. There is nothing "communist" about any of this, except that the people in charge of it called themselves Communists. Just as they called themselves democrats. Since we don't take the latter self-designation seriously, why do we take the former seriously? Because we've been indoctrinated. With a very stupid ideology: e.g., that the Cold War was between "democracy" and "communism."
If you want to remember what communism really means, remember its derivation: commune-ism. The Soviet Union was hardly a bunch of communes. It was kind of the exact opposite of that. In reality, the Cold War was fought between two types of state capitalism. But you'll hardly ever find this fact expressed in scholarship or popular writings, because intellectuals are ideologists, not scientists.
Anyway, this rant has gone on long enough. My point is that it's useful to look at the world through a kind of gestalt switch: instead of our usual attitude of taking people and institutions seriously, we should, at least sometimes, be attuned to the intense stupidity of nearly everything. We should also be on the lookout for stupidity in our own thinking and behavior; one way I try to avoid that is by asking myself, in the mode of a Jesus-worshiper, "What would Chomsky think/do?" Whatever he's like as a person, I've found that as an abstract ideal he's a useful "regulative principle" of thought and action.
 Class oppression obviously isn't the only kind of oppression, but it's very, very important.