Kid was an idiot
The cops were idiots, improperly trained.
emotions too high strung all the way around on this one.
At the point where the kid offered physical resistance, which risks escalating the conflict into something deadly (the officer must be prepared for him doing something drastic, like trying to grab his sidearm), the officers (who overwhelmingly had the upper hand) should have IMMEDIATELY flipped him, cuffed him, and carried him out. End of story, let him cool off while in holding, and that's it.
I have great respect for law enforcement, but I'm afraid that the standard keeps lowering for this field. The dumbing down of our society at large is producing an 'us-vs-them' attitude on both sides of the badge, and many who wear that honor care more about a stack of benefits (health, retirement, decent pay, cops have it much better off than you think!) and being able to push people around, than actually serving the public which pays their wages. I say this in general, but that doesn't take away from the inspiring sacrifice and ethics of a great many officers in our nation today. It varies drastically from area to area, and our finest are so because of training and leadership from above. Without that vector of success, you get the dangerous unprofessionalism that is evidenced by this incident.