Disagreement, even loudly vocal disagreement, is not censorship. Neither is it censorship to declare that you do not wish your tax dollars or tuition fees to go towards providing a platform for views you find odious or insupportable, any more than it would be to, oh, I don’t know, localize a video game or some such similarly innocuous act. Schools are not required to provide equal time for the teaching of ‘intelligent design’ in biology classrooms, for example.
As for blocking entrances, it’s one of many forms of protest, most notably in the civil-rights & anti-war movements in the 60s, common to university campuses, which are where a lot of people discover their political consciousness. Again, it seems a logical byproduct of exposure to new ideas.