You had one cop leg locking him on top while another cops is beating the hell out of him. Tough to show you're capitulating at that point with two cops working you over. Not to mention before the beatings started the kid was laying on his back with arms up.Just playing devil's advocate here, but it's often difficult to tell when someone is resisting - I've seen quite a few videos where it looks like an officers is using way too much force only to later see his body cam that clearly showed the subject fighting to avoid being cuffed.
Regardless, of what transpire before the nearly 3 minute long video started the rolling, the threat posed by that kid not justify the abuse given. You can tell it was vindictive by the initial cop coming back and jerking that girl who ....ed him off onto the concrete.