> officially sanctioned by the school

You interpret the anecdote as involving something official? I interpreted it as pertaining to social norms being enforced by only the students themselves. Kids hassling each other for "playing nonexistent white/straight/male cards" or "playing a card they don't have" is quite different from authority figures imposing equivalent policies. I mean, on some level the subject of the enforcement is in a similar position regardless of the nature of the enforcement, but we should at least agree on what we're dealing with here.