Well, by the account of the person that thinks the cops are in the wrong:
Person the computer lab with no ID refuses to leave when cops first approach.
-So right there, the cops have every right to remove the kid. But they don’t. They leave for some reason that really isn’t relevant either way.
The cops return, the kid is still there.
-Walking to the door, walking around the lab, again irrelevant. He’s still trespassing since he has no ID proving he has a right to be there. The cops have every right at that point to take said person by the arm and make sure he does indeed leave the premises.
The guy then starts screaming let go of me.
-The cops have no legal obligation to let go. The kid lost his chance to leave without an escort when he refused to earlier. Let the cop lead you out by the arm and move on.
At this point the video takes over. Had it shown him getting beaten or shot, ok, I’ll buy the excessive force thing. But the kid got shocked by a taser after acting like the rules didn’t apply to him. Tough shit, take your shock, maybe learn a lesson, and move on.