Experts say he over-reacted.
He is a man of 5 foot 5 or 5 foot 6. He was shorter than the mean little girl that he tossed to the ground. His pride was hurt when he ran after the kids and he fell and busted his ass. He was yelling and cursing at children. He was forcibly throwing people to the ground when his own partners were actually acting like professionals.
Notice how the other normal sized officer in the beginning was talking to the young boys like a human. Then this bozo pint-sized man runs in like a bull in a china shop.