To clarify, I'm not defending the question that were asked on that interview. That's not learning, that's trolling (or else an astounding depth of ignorance). My remark was in regard to the general concept that, yes, we should be actively seeking to learn about other people's experiences, and you really can't do that without asking questions (and no, spending time with them is not a substitute, since you can't spend it from their POV - although it is also a valuable learning tool).
That said, even misguided and offensive questions like that are not as meaningless as they seem, given the right context (which, again, obviously wasn't a case in that interview - but could be a case in, say, a study on the subject). For example:
>> What decisions are you making that are based on questions like "why do black people sit together at lunch?"
If the answer involved discrimination or exclusion by other students, which is the most likely explanation based on everything else, then those are issues that need to be addressed. And even if this is outside of your personal area of responsibility, at the very least, you have a moral responsibility to ensure that the people who you elect and/or fund who are responsible for it, pay appropriate attention.