WOW, You are right it is these kind of idiots that push kids OFF. But more so, they are NOT practicing Yiddishkeit, they are practicing their own selfish need for power. No one has the right to touch your child. You tried to go the nice route by allowing him to as mechila from your child. He refused. Now it is time to follow the Law because this man believes he is above the law. He believes he is and ENFORCER. He is nothing but a bully, and the only way to stop a bully is by teaching him a lesson. I am sure this is NOT the first time he has done this nor will it be the last. He did not hesitate to attack your son and he stood firm in his position NOT to ask mechilah.
It is time to report this to the authorities and keep the rest of the children in the neighborhood safe. He must be stopped. Please remember he didn’t he slap him on the hand, he knocked him to the ground. That is assault. Be a hero for your children. You don’t have to follow through with charges and court afterward, but this man needs to be hauled off to jail.