Simple.
Society promised a comfortable, middle-class living for those who went to school.
The problem was, there were never enough of those jobs to accommodate the rush of new college students, and on top of that, automation has increasingly cut away the good-paying working-class jobs that used to employ their parents and grandparents. Now all we have are human services jobs.
So, with a generation of people with a huge amount of debt, a worthless degree and no way to monetize it, we have a desperate throng looking anywhere to help them get out of this mess. They see rich people, and they see a target.