There’s plenty of useful idiots that will show up as warm bodies. But, the hardcore, rock-throwing, police-assaulting demonstrators are either for hire, or local criminals seeing an opportunity. Somebody’s renting the buses and printing the signs.
As to political indoctrination, I remember those days. In the early days of political correctness I thought it was an Emily Post of discourse. Stupid, restrictive, unnecessary, silly. I had no idea how oppressive and prevalent it would become.
I do have some boys who got out of college about ten years ago, and are more in touch than I am. They say that although it is politically oppressive on campus, it doesn’t affect people that are trying to learn something non-political, like STEM, because they have neither the interest or the time to waste on this foolishness. But, they also admit it’s gotten a lot worse in the ten or so years since they graduated.
Exit polling by STEM college grads vs other degree grads would probably show a big tilt towards Trump. That would be a very interesting piece of data