Basically, they target vulnerable people who have an earnest desire to approve themselves or access to someone else’s money. They advertise outcomes — “wouldn’t you like to be a respitory therapist making $75k” vs. courses of study and admit people to programs they are unqualified for. Then they pump you dry.
As a middle class person, it’s difficult to appreciate the mysterious nature of things without trustworthy advisors. A close friend came from a blue collar background and didn’t get good counsel. Her parents were thrilled that she got into college, which had been seemingly impossible for them.
She ended up getting a package of loans and scholarships that ran short at the end of her studies. Fortunately, in the 90s these predatory student loans weren’t as common, and she ended up putting $50k on credit cards to pay for her last 3 semesters, and was able to go bankrupt after a few years.