Good story!

I read a Buddhist proverb years ago and it went (approximately) like this:

A monk was walking down a road minding his own business. A group of young men approached him, taunted him verbally, then knocked him to the ground. A man who observed this act ran over and helped the monk to his feet, dusted him off and looked him over for injury. The rescuer verbalized his disgust with the act he just observed and offered to catch the men and bear witness to the law on the monk's behalf. The monk kindly thanked the man for his service but told him "Don't worry about it...that's THEIR problem, not mine".

So if you are not a Buddhist, you have certainly come upon some good wisdom on your own. Good on ya!