He's limiting the disruption on college campuses, where students (and the federal government) pay for attendance and education, by not providing any federal aid if that occurs.
They're more than welcome to protest in public parks, etc., or where permitted. However, I don't feel a college campus is the right place to do it, especially considering my education was $25,000 per year, and if I weren't getting what I paid for, I'd be pissed. I'm sure a lot of students feel that way about protests on campus but won't speak out about it due to the backlash they'd receive from the lunatic lefties engaging in such activities.
I see nothing wrong with that.
It'd be much like a protest taking place in a Wal-Mart. You'd essentially be making the customers uncomfortable to be there. What should Wal-Mart do in that instance? 86/trespass them for their disturbance.