Reading the Oberlin College complaints about the food, I note that what they are actually complaining about is that the ethnic food is not prepared in an authentic fashion. The rice is steamed instead of fried, or whatever.
So it's not about appropriation, it's about snobbery. There have always been people who like showing off that they know oh-so-much-more than you about a culture and its customs. Screwtape notes that men in particular are prone to demonstrating that they know the only place in town where they prepare steaks properly, and this seems related. Students are trying desperately to tie this in to some prejudice that you just don't care about Vietnamese/Mexican/Caribbean people as much as they do, and are hence some sort of bigot, but it's all just old-fashioned snobbery. They know which fork to use and you don't.
Thinking back on the other recent controversies about prejudice on college campuses, I find that this framing does indeed fit. We don't really wear sombreros, you ignorant bastards. Well, lots of you used to, some of you still do, and it's actually a pretty good hat design for intense heat with no AC. It's not me rejecting your culture, it's you. Now that your family is upper middle class - I'm sorry, you did notice that it's not those other Mexicans who are getting the benefit of affirmative action, didn't you? - and doesn't work in the sun, you want us to recognise that by removing all sombreros from our consciousness. Frankly, it sounds a bit like my social-climbing grandmother, a 2nd generation Swede who looked down on French Canadians, Greeks, and certainly anyone dark.
And you white people who want to show that you really "get it" about the food of other cultures? Yeah, we used to see that when Junior Year Abroad was the main vector for learning about other countries.
Let me state it again: liberalism at this intensity is not in the least about any intellectual arguments. Which is a pity, because liberals actually do have some pretty good arguments, they just don't use them. It is a social acceptability phenomenon. It is fair to say that a certain type of conservative does the same thing about being a really true American/Republican/Conservative. They have their filters, and you pass through them or you don't.
Hey, here's a fun one on the conservative side: the best-sounding defense of support for Donald Trump is that he really gets it about immigration, while the GOP elites just don't. Except...Mitt Romney was the person who actually got it right, vetoing illegal immigrants getting Medicaid, free college tuition, and housing subsidies. No one cared, no one noticed. Did you guys care then? No, you called him a RINO. My charge is that you decided he didn't "feel" like one of you because he's a rich hedge fund guy from the Northeast. No more, no less.