Analyze it:
A college sponsoring or hosting an event or class assumes responsibility for what happens.
Some student becomes emboldened to "save the day" as a result of the class, and gets hurt.
Legal troubles follow the publicity that crops up immediately.
The buck stops at the administrator, who's left holding a $hit sandwich.
How many "defense instructors" are credentialed college professors, coaches, or instructors, anyway?
There are many risks for the college, and the only plus side is that students might learn something valuable.
The latter case has never offset the former situation yet, so you're going to have to come up with a "socially, politically, and legally acceptable" way to eliminate the risks to the bureaucrats who run the college.
My guess? It ain't gonna happen because it complicates things for the administrators....