"What is a "left wing" student supposed to think a university endorses the appearance of a speaker who makes wild anti-liberal statements? They would, no doubt, feel that certain of their professors might penalize them unfairly."
Penalize them unfairly of what? Of attending a speech by someone who was invited by other students? Really? 
And the university doesn't endorse any speaker invited by students. They just allow the students to use the space. As long as they don't prevent other political views being heard then they are not endorsing any particular viewpoint. They are in fact doing their job - to expose students to as many competing philosophies as possible. 
And that is what I think the campus left is truly afraid of - don't let your opponents speak because the might be more convincing than you are... and that's why they are scary in a way that the right isn't.