Why are some of the most privileged students in the nation plunging into a racial grievance culture and upending their campuses as though oppressed by Halloween costumes they don’t approve, imagined racial slights, portraits of Woodrow Wilson, a tiny handful of real racial epithets, and the like?

The reasons are of course multifaceted. But one deserves far more attention than it has gotten: Many or most of the African-American student protesters really are victims — but not of old-fashioned racism.

Most are, rather, victims of the very large admissions preferences that set up racial-minority students for academic struggle at the selective universities that have cynically misled them into thinking they are well qualified to compete with classmates who are, in fact, far stronger academically.

The reality is that most good black and Hispanic students, who would be academically competitive at many selective schools, are not competitive at the more selective schools that they attend.

That’s why it takes very large racial preferences to get them admitted. An inevitable result is that many black and (to a lesser extent) Hispanic students cannot keep up with better-prepared classmates and rank low in their classes no matter how hard they work.

Studies show that this academic “mismatch effect” forces them to drop science and other challenging courses; to move into soft, easily graded, courses disproportionately populated by other preferentially admitted students; and to abandon career hopes such as engineering and pre-med. Many lose intellectual self-confidence and become unhappy even if they avoid flunking out.

This depresses black performance at virtually all selective schools because of what experts call the cascade effect. Here’s how it works, as Richard Sander and I demonstrated in a 2012 book, Mismatch: How Affirmative Action Hurts Students It’s Intended to Help, and Why Universities Won’t Admit It:

Only 1 to 2 percent of black college applicants emerge from high school well-qualified academically for (say) the top Ivy League colleges. Therefore, those schools can meet their racial admissions targets only by using large preferences. They bring in black students who are well qualified for moderately elite schools like (say) the University of North Carolina, but not for the Ivies that recruit them. This leaves schools like UNC able to meet their own racial targets only by giving large preferences to black students who are well qualified for less selective schools like (say) the University of Missouri but not for UNC. And so on down the selectivity scale.

As a result, experts agree, most black students at even moderately selective schools — with high school preparation and test scores far below those of their classmates — rank well below the middle of their college and grad school classes, with between 25% and 50% ranking in the bottom tenth. That’s a very bad place to be at any school.

This, in turn, increases these students’ isolation and self-segregation from the higher-achieving Asians and whites who flourish in more challenging courses. At least one careful study shows that students are more likely to become friends with peers who are similar in academic accomplishment.

Put yourself in the position of manyHispanic and especially black students (recipients of by far the largest racial preferences) at selective schools, who may work heroically during the first semester only to be lost in many classroom discussions and dismayed by their grades.

As they start to see the gulf between their own performance and that of most of their fellow students, dismay can become despair. They soon realize that no matter how hard they work, they will struggle academically.

It is critical to understand that these are not bad students. They did well in high school and could excel at somewhat less selective universities where they would arrive roughly as well prepared as their classmates.

But due to racial preferences, they find themselves for the first time in their lives competing against classmates who have a huge head start in terms of previous education, academic ability, or both.

Researchers have shown that racial preference recipients develop negative perceptions of their own academic competence, which in turn harms their performance and even their mental health, through “stereotype threat” and other problems. They may come to see themselves as failures in the eyes of their families, their friends, and themselves.

Such mismatched minority students are understandably baffled and often bitter about why this is happening to them. With most other minority students having similar problems, their personal academic struggles take on a collective, racial cast.

Consider the case of a student whom I will call Joe, as told in Mismatch. He breezed through high school in Syracuse, New York, in the top 20 percent of his class. He had been class president, a successful athlete, and sang in gospel choir. He was easily admitted to Colgate, a moderately elite liberal arts college in rural New York; no one pointed out to Joe that his SAT scores were far below the class median.

Joe immediately found himself over his head academically, facing far more rigorous coursework than ever before. “Nobody told me what would be expected of me beforehand,” Joe later recalled. “I really didn’t know what I was getting into. And it all made me feel as if I wasn’t smart enough.”

But just as surprising and upsetting was the social environment in which Joe found himself. “I was immediately stereotyped and put into a box because I was African American,” he recalled. “And that made it harder to perform. People often made little derogatory comments.…There was a general feeling that all blacks on campus were there either because they were athletes or they came through a minority recruitment program.… That was just assumed right away.”

It was also, unfortunately, quite true. That’s why racial preferences are an extremely powerful generator of racial stereotypes about intellectual abilities. Joe was forced by bad grades to drop out after his freshman year, though he eventually returned to Colgate and obtained his bachelor’s degree.

Not many mismatched students complain — even if they figure out — that the root of their problems is that they are not well-qualified to compete with their classmates. The universities, the media, and others do their best to conceal and deny this connection. And it is human nature to seek less humiliating, more sinister explanations.

The grievance-prone college culture offers ready targets for these frustrated students to blame for their plight: wildly exaggerated and sometimes fabricated instances of racism, trivial perceived “microaggressions,” and the very real racial isolation that is largely due to racially preferential admissions — all leading to a supposedly hostile learning environment.

Another common reaction is to withdraw into racial enclaves within the campus. Many universities encourage this by creating black dormitories and even by assigning entering students to them.

Racial, intellectual, economic, social, religious, and political diversity can greatly enrich the educational experience — but not when engineered through large preferences that do more harm than good to their supposed beneficiaries, not to mention to the stronger students who are passed over to make room for racial-preference recipients.

All this goes a long way toward explaining the over-the-top demands now roiling our campuses for still more racial admissions preferences; more preferentially hired, underqualified professors; more grievance-focused courses and university bureaucrats; more university-sponsored racial enclaves; and more apologies for “white privilege.”

The university leaders who cravenly coddle the racial grievance lobby, such as Yale President Peter Salovey and Princeton President Christopher Eisgruber, are only aggravating academic mismatch, racial isolation, and unhappiness among minority students — and degrading their own universities.

Pessimistic observers of such meltdowns conclude that our most prestigious universities are committing suicide. Where are the leaders who will set things straight?