This age of p.c correctness on college campi coincides with the rise and dominance of females on campi. Females are now the majority of most of the nations's campi. It's well known that male (often very nasty) humor does not go down well with females.
Add to that the growth of the femi-nazis i.e liberal fascists who proliferate on college campi, and you have the ingredients of the p.c. culture where nothing untoward is permitted.
...But almost all of them have internalized the code that you don’t laugh at politically incorrect statements; you complain about them. In part, this is because they are the inheritors of three decades of identity politics, which have come to be a central driver of attitudes on college campuses. But there’s more to it than that. These kids aren’t dummies; they look around their colleges and see that there are huge incentives to join the ideological bandwagon and harsh penalties for questioning the platform’s core ideas.