If you take out the 'technically' from that statement - as you should - then I would still disagree with it.
This lad is already committing adult criminal acts, and is ready to see how society reacts and punishes him. it is clear that his father's habit of 'clipping' him has shown only his father's inability to keep his temper and discipline his child properly and appropriately.
Now the child has seen his own father treated like the criminal he is - and maybe that will be more of a lesson to him than random violence from a short-tempered bully.
My father was fond of 'clipping' me - he kept it up until i was in my twenties (bullies can always establish a hierarchy, age is irrelavent) - until one night I answered back and he came at me with a pair of kicthen scissors. I was merely waiting until he got close enough, so i could get hold of them, and the result would have been a fatality for one of us, had my mother not intervened.
This kind of 'discipline' is not appropriate - it is violent bullying - and it failed this child, as it failed me. My only lesson was never to hit my children in the head or face, or allow them to do the same.
if this lad is going to learn that actions have consequences - a dispassinate legal system may succeed, where his ignorant bullying criminal father with his violent temper has failed.
let's hope so.