I'd say a women going up and punching a teenager and throwing a bike into the middle of the road is actually, pretty bloody crazy.
She could have gathered evidence. She could have taken photographs. She could have gone to the police with that body of evidence and said "Look - I know you're too busy - here are the guys in question, here's the evidence you need, sort it"
But no, she tried to take the law into her own hands - and got violent. Violence was not the answer...but then, I wouldn't expect you to understand that Tom.
Or, are you trying to tell me that in the whole of the United States, there aren't kids doing bad stuff. No kids smashing bus stops, phone booths, parks etc, in the knowledge that the police don't have the time or the power to do much about it.
How would you deal with rowdy teenagers Tom? Shoot them? Throw them in Jail so they can gain a drug habit and make some new friends. What's your solution Tom? Vigilante street violence? That's what you're advocating here.