Here, the students were admitted, presumably with knowledge of these facts, and don't yet have a credible claim to any effect other than hurt feelings.
> I don't see how that isn't institutional discrimination.
Discriminating against people who get offended isn't unlawful. Not every instance of discrimination deserves to be righted. (If I kick you out of my perfume store because you smell like a distillery, the law does not, and should not, protect you.)
> What if it included writing an essay on "why bullying nerds are good for them" and people who've benn bullied couldn't do very well on that assignment, because they obviously took offence, is that not discrimination?
No, it is not. Again, there's no right to be protected against assignments that conflict with your upbringing. (In fact, one of the main goals of higher education is to make you see things from other points of view, even if they disturb you.) If you were offended by it, you'd be well off to still do the assignment but provide a strong counterargument instead.
You appear to be saying that it's okay for people to call black colleagues niggers, and for the college to do nothing to support that black student because fuck them, hurt feelings, and that the long history of brutal racist treatment of black people in America should be ignored by any black people when someone calls them nigger.
Is that what you're saying? Because I can't find another interpretation.
First, none of the situations discussed involve the N-word, so what you're describing is a hypothetical example, and a very special one at that. I think it's expected that a professor or staff member would be fired for hurling racial epithets.
Students, on the other hand, are a different case. For them, it's the institution's duty to intervene and help resolve the conflict, educate the speaker about the historical background, help instill empathy, and counsel the victim. Academic probation is often a tool that can be used if the problem cannot be resolved, but expulsion is typically the second or third step, not the first.
What if it included writing an essay on "why bullying nerds are good for them" and people who've been bullied couldn't do very well on that assignment, because they obviously took offence, is that not discrimination?
The debate team doesn't get to choose which side they argue. It's assigned randomly. More people should do that because it actually increases empathy.