Actually, it seems to be the dominant ideology on college campuses now - you see it from top to bottom ... administration, academics and students. It is extremism but it's not "extreme" as in unusual as you are trying to make out. Just as black students shouldn't feel that they are threatened just for attending somewhere, neither should anyone who has conservative views - but that is now the reality on campus and it's an utter disgrace. This is how they treat people who are on their side!!!
There needs to be:
Strong condemnation from media and onlookers / commentators
Action by administrators and removal of people doing this kind of thing
Withdrawal of funding for colleges and universities that don't
Expulsion of students that threaten and physically assault people (as has happened in other cases)
None of these things will probably happen because the left now only values shouting and punching.