Of course if it had been a gang of white youths attacking a black youth they'd be banging on about it 20 years later and brass plaque would mark the spot.
I think all he needed was a good few slaps. He would be sorted for a while and in few years he'll probably thank the person for slapping some sense into him.
Or he might just do what someone I know did, get a knife and **** up the person who beat him.
So please, go ahead and condone violence against the youthful troublemakers, it couldn't possibly backfire in your face like it does in every 3rd world ****-hole, by creating an anti police "gang" culture.