It also can get tragically out of hand.
Live on the edge, die on the edge.
IMHO the officer reacted as any reasonable person would have.
The results were nearly tragic.
I believe such conduct of wrestling dogs and mock dog attacks in public is highly inappropriate, no matter where it is conducted. Do it at home in your yard of you have to.
A reasonable person would NOT have fired before at least ASKING the "victim" in some way if they needed help. Personally, when I come up kids wrasslin'/playin' like that, I yell LOUDLY to get their attention. If they don't, then I can take further steps. I do not start hosing them down with a flamethrower on sight.