I doubt many people would object to the officer's punching the kid to get him to release his testes. It also doesn't seem from the video like this is the case-- i.e. that the kid was holding the officers testes at the time he was struck on camera. So again you are being unclear. Assume (for hypothesis) that the kid had grabbed the officer's testicles prior to what's visible on the tape. In your view, does the officer then have the right to slam the kid into the car and punch him once the testes have already been released and the kid is under control?