The other people around him. The ones the druggie was scaring the shit out of. Those people. Penny didn't just walk up to some random person and decide to put them in a choke hold.
Did you also miss that that poor needs help criminal had been arrested numerous times prior for assaulting people? Yep, poor lil dude - maybe if the idiot criminal system there had done their job and imprisoned him for one of those crimes, he might have gotten some "help".

The other people around him. The ones the druggie was scaring the shit out of. Those people. Penny didn't just walk up to some random person and decide to put them in a choke hold.