Very true. What I would expect from a large, high quality, institution is a broad variety of different viewpoints aired.
It depends a good deal on what turned away means. Nobody can host an unlimited number of guests. You have to exercise some discretion.
But it's something else entirely to cancel part of that broad array because some students don't want the views aired. That happens all too often.
Tom
I think it's more accurate to say that it's because the university has concerns about its reputation, not necessarily that people don't want the views aired at all.
When a speaker speaks at university, it can be taken of an endorsement of the speaker’s views by the university. It’s entirely appropriate for a university to make sure that this implied endorsement is only given to speakers that the institution wants to be seen as endorsing.
As for cancellations... I think this often comes down to poor communication within the university itself: typically, a student group will try to organize a speaking event and expect it to fly below the radar, but then something happens to bring attention to the event, which is when the top levels of the university administration become aware of it. Generally, it isn’t that the university makes a decision and then reneges on it; it’s that the university institutes general guidelines, but a group on campus does something that goes against them. Because the administration doesn’t monitor everything that student groups do in detail, they aren’t able to rein the group in until the event has some publicity.