Very interesting thought, that colleges' purpose is to acculturate one into a certain culture. That would explain why collegiate athletics are so important: because people of a particular college's culture place importance on chasing after balls on grassy fields, it's important for colleges to acculturate their students to watching people chase after balls on grassy fields. I'm not saying that sarcastically — as much…
while your points are true, its kind of the whole point of the article is 'economic' (and of course race) are first-order approximations of 'social' class but they are NOT the same thing, only approximately overlapping. Pretty much the whole point of the article.
In general, of course, I find the idea of announcing 'derailing' topics to be ridiculous, meaning something like, 'here are my thoughts on a topic: you are free to talk about your thoughts in these related areas, but not those related areas, because I don't want you to, and will consider you rude.' It feels childish to me.