He obviously has a very limited viewpoint. He thinks the way things are, or at least he thinks they are, in his location is the way they are everywhere. We've clearly shown him it's not true with regards to lawful use of lethal force, and I'm sure you could show him the statute law showing it's not true about the repo business either.
I'll bet he doesn't break into houses to collect debts either. That's what making off with a vehicle without the registered owners permission is equivalent to doing.
BTW, at least in Texas, the loan company keeps the original title to a vehicle until it's paid off, at which point the state issues a new "clear" title to the owner. So it's sort of "joint custody" until then. Been there, done that, at least 7 times now. Plus wo still in the "joint custody" state (both 03 Mazda 6s, one my wifes, the other my daughters).
As far as I know, repossessors give advance prior notice before repoing a car. Additionally, the UCC allows self help to recover collateral. Are there abuses? Of course.