There are 2 sides to every story....
Sleazeballs, yes, but if they aren't offering loans to high risk buyers, these folks will not get a car, period. There is a reason Buy Here, Pay Here places exist. Same for the Payday Loan places. They "prey" on low income but "prey" can be described as "provide a service" too. Making them illegal just feeds the loan shark on the corner. THAT guy will do far worse than repossess your car!
The buyers also didn't follow the suggestions we tell every used car purchaser that posts here - get it inspected first! And the second, do your homework on the actual value of the car and third, don't buy to the limit of your ability, hold some back for service.
Yes, the people who take knowingly advantage of these buyers are slime. These same dealers are the ones who put immobilizers on cars to shut them down if the payments aren't made. They did this because there are buyers that walk in, put little to no money down with no intention of ever paying back the loan. Much like taking the car to a mechanic and trying to weasel out on "full payment or no car". THOSE folks are the sleazeballs on the other side of the transaction. They take advantage of the honest merchant.