so it's ok to have pro-lifers on campus but if there's a kitten petting station that's beyond the pale

People are free to pet whatever they want on campus. You've missing the point the example, which isn't to say "No petting kittens," but to say, "This is about more than just Halloween costumes," in response to your claim that none of the attitudes of the protesters carry over into specifically academic speech.

hat comes up time and again in these discussions, 'free speech' means 'free to say what i want' and protesting against what you say is 'stifling free speech'

People can protest all they want. But protests that aim at drowning out certain voices or making sure that certain perspectives don't have a presence on campus simply is stifling the free exchange of ideas.

and again, controversial material in the classroom is a different thing.

Once again, academic communities are far more than just classrooms. A guest speaker at an event on campus is every bit a part of the academic life of the campus as the classes are, and if protesters are trying to force certain speakers from the right to speak on campus, they're interfering with the academic life of the university every bit as much as if they were doing it in the classroom.

And once again, it's not clear to me why you think that protesters who want to shut down free expression of ideas in all other areas of university life are going to consider the classroom uniquely off limits.

if someone is teaching 'controversial' material they should be well aware this is going to generate some heat and light and not play scared of 'being shut down' because people express vigorous disagreement with them.

I'm sorry, but I'm beginning to think that you simply don't want to listen to what's being said. I don't know how to emphasize this in a way you'll understand: I am absolutely not denying people the right to express disagreement. I invite the expression of disagreement, because that's a crucial part of the free exchange of ideas that I'm defending. Nothing that I'm talking about has to do with expressing disagreement; it has to do with trying silence voices that are deemed offensive. Faculty without tenure protection aren't risking having their feelings hurt because somebody disagrees with them; they risk losing their livelihood when they're accused of racism or some other offense.

there are plenty of vigorous debates about what is and isn't racism.

But why would I want to be involved in those debates if there are people who will want me to lose my job if the position I take is one they deem racist? If racist speech constitutes a compelling reason to ostracize someone, then why would I want to take the risk of possibly arguing the wrong position?

academia tending liberal in a world where power tends conservative is a little bit more complex than this.

This is the experience that gets reported time and time again by conservative academics/ex-academics. Why is it that their experiences don't count here?