Just the noisy ones get the media attention. They have infested the student publications since I went there 60+ years ago.That has already been a liberal hotbed.
That helps explain their progression. They started as naive college kids protesting all sorts of issues so they could feel good about themselves. One of their main issues was mean professors. (Well, it was a little more complex than that. )After the USSR collapsed 30+ years ago, it was revealed that the KGB was “subsidizing “ the SDS.
The MSM pretty much ignored that bit of scandal.