The OBVIOUS POINT HERE is that if these universities were SO SURE the validity, common sense and rightness of their leftist views, rather than block conservative speakers, they would WELCOME THEM and invite the campus to hear BOTH SIDES then decide.
Since conservatives are obviously SO WRONG, what better way to PROVE IT and let conservatives make fools of themselves?
But instead, the Fascist Left universities only teach fascism and hate to their students. It's the only way they can survive, without challenge to their ideals and thinking, the epitome of weakness.
The weakest position is the one where you can convince others your position is actually SO STRONG that it is BENEATH YOU to even consider the other POV. THAT is the Left's safety valve.