I haven't seen the video image of what you are talkig about but from what my wife tells me I am wondering about all the fuss.
When I was a kid my parents told me if someone hit you you hit them back, boy or girl didn't matter.
Also from what I have been told the smaller kid hit the larger boy 3 separate times ...........what was he supposed to do........turn the other cheek ?
This is something that happens in schoolyards across the planet on an daily basis, the only reason we are discussing this is someone recorded it which seems to indicate a kid had a recording device at school and in this day and age could be no more that a mobile phone, there in lies another problem with society, something old farts like me can not comprehend.