One theme of this blog is pondering why educational elites are disproportionately interested in dimensions of diversity that don't relate to social or economic class. Certainly there are sound moral reasons for attaching high significance to ethnic diversity (frankly, if I were pulled over by the police I'd sooner be a poor white man than a black man of any class, even a politician). Then again, there are also valid moral reasons for treating class more seriously than it's currently treated in many academic environments. Ultimately, it's a value judgment, and the question is why people judge it the way they do. (I should be clear that treating it as a value judgment rather than a matter of objective fact is not to trivialize it. Some of the most important issues in human society are value judgments, and the fact that values are ultimately just, like, your opinion, man, does not make the stakes any lower or the moral significance any lesser.)
America's educational institutions are institutions dependent on the patronage of the state and the upper classes (via donations), and a large part of their task is to train people for public service, whether we're talking about people studying criminal justice before going on to law enforcement careers, ROTC students, or Ivy League schools training future Cabinet Secretaries and Supreme Court Justices. The United States government has many sins to answer for, but in two crucial political conflicts the US government came down on the better of the two sides. Both of those conflicts involved race, and both involved existential questions for the government's power: The Civil War and the Civil Rights Era.
In the Civil War the authority of the federal government was challenged in the starkest terms possible, and the root of the controversy was slavery. Say what you will about state power, or economics, or whatever else, but the state prerogatives in play concerned slavery, and the economic issues concerned the needs of a slave-dependent economy. The federal government was on the better side there. There's much to be said about the federal government's failures regarding the rights of African-Americans after Reconstruction, but it is ingrained into the institutional and cultural memory that the starkest challenge to our political institutions concerned race.
The next starkest internal challenge to the authority of our political institutions concerned the ending of de jure segregation (not to be confused with de facto segregation). Southern states tried to openly defy the feds, resulting in National Guard troops being deployed to desegregate schools, and numerous federal court cases and Department of Justice civil rights actions starting in the 50's and continuing to the present.
Race in America is thus an issue where the existential imperatives of public institutions are intimately entwined with moral imperatives. Seen in that light, it makes sense that institutions that exist to serve (in part) the workforce needs of public institution would prize racial and ethnic diversity over class diversity. We thus have a mix of sound moral concerns (like I said, a case can be made that race is rightly more important), institutional imperatives (at its core, the state will preserve its own authority), and somewhat hypocritical class sympathies. Like any cultural fact on the ground, it is neither wholly pure nor wholly tainted. It is tied into the good and bad of human history.
I said a few weeks ago that in the era of Donaldik Fydorvich Trump academia will no doubt damp down some of its internal political tensions in order to unite against a common outside threat. While I hope that some sort of sincere effort to improve the lot of the working class in the Rust Belt and small towns might emerge from the post-election soul-searching, this is me recognizing that there are deeper historical reasons for our focus on race, and in the era of an unabashed bigot in the White House it is appropriate for reasons of past, present, and value judgments that racial and ethnic diversity not exist our moral calculus.