“The video shows the perp saying something to the cop that he didn’t like. “
So what?
Well, some people have no impulse control and can’t stop to think “hey this is all going to get caught on camera” if someone triggers their sensitive wittle feewings.
Screening process for cops should probably screen for that. I imagine the military screens those people out pretty well by letting drill sergeants scream all kinds of abuse in their faces and then seeing which ones can’t take it without cracking.