I am a LEO. I think that in this case, the cop went overboard, and should be held accountable.
I would add though, that most videos of this type do not capture what the “victim” said, or did before the action taken by the LEO. I have to get physical with people, but only as an absolute last resort. I’m sure there are plenty of times that someone could start filming me after a guy spit in my face, or swung on me, or hit a girl, or did an eight ball of cocaine, or tried to fight a crowd of people, and see it as deplorable.
When someone has to be removed from somewhere, and they refuse to move, you have to move them. That’s the job. You don’t have to be a jerk about it, and you never take it personally, but sometimes you have to resort to a form of restraint, or violence.
Hopefully, the new body cameras will keep LEOs from overstepping, and keep them protected by showing the whole story.