They predate students with false claims of future employment and encourage loan-taking, thus profiting off the federal loan system knowing full well that they’re not actually helping you find future employment. They’ve been investigated, lost some court cases, then were more or less let off the hook by Betsy DeVos, a charter school fanatic and free market fundamentalist.
On the other hand, they want your money and have a mandate to get as much of it as they can or face potential lawsuits from their shareholders.