I tried looking up some threads about this fight, but it seems that people are under the impression that jo overreacted to. It was incredibly wrong for alex to beat up deluca, and it was also incredibly wrong and also illegal for jo to beat up jason.

Who Beat Up Jason Myers In Grey's Anatomy
And all jason did was try to beat her back. He fell and hit his head and wound up with a brain bleed. If the cops had been called, both jo and jason could've gone to jail but jo would not.