Ok, so a population that is majority not at-risk and extraordinarily self-contained is going to be instead distributed into the wider population en masse? Seems insane.
MIT is not "self contained," it's in the middle of the Boston metro less than a few miles away from dozens of other schools including large universities like BU and Harvard.
The university can send most of its students home. It can't stop the rest of the world from interacting with them in the middle of a regional hub.
I think most students would be more self-contained off-campus. Going entirely online helps, but I wouldn't call college downs clean. Clearing them out is a good idea.
What would instead happen is that students would go on spring break, quite a number of them traveling of town. Some of them would pick up the virus and then it would spread among the student body over the remainder of the semester. That's a plausible scenario that no university would want. Better to have them go home and stay there.
The university can send most of its students home. It can't stop the rest of the world from interacting with them in the middle of a regional hub.