Why is it wrong? Some car thieves got beaten. I regard that as a good thing.
It's unfortunate, isn't it?
In the Bronx a few years back some guy was sent to jail for shooting some slimebag for trying to steal his car (the car had been stolen many times before).
Of course the car owner was a fool--he should have realized the only smart thing to do was to move from a criminal area--but perhaps he was trapped by circumstances and had to live there.