It's bad enough to watch this cop beat a man who is lying on the ground with his baton. They were trying to cuff him for whatever reason, and the guy was not being 100% cooperative, so it looks like the cop started swatting him to coerce some cooperation.
But what's worse for me is 1) after the baton flies out of his hand, the cop goes to retrieve it so he can beat the guy some more; and 2) After whacking the man on both knees, the man is clearly in serious pain and starts holding his left knee, and the cop specifically hits him again and again on that injured knee.
Man's inhumanity to Man. That guy wasn't going anywhere. The officer was venting; it's that simple, and it's that wrong.