After watching the entire video, I don't think the boy is completely innocent. The officer was calm at the beginning. They boy gave him an attitude and kept saying "I didn't do anything." Obviously he was skating in an area that had "No skateboarding" signs. He didn't listen when the officer told him to sit down. The officer shouldn't have made the comments about slapping him, or saying the kid's father should have put a boot in his ass. The officer was out of control, but the kid was being a little jerk.
Sorry, but when you're 14, police officers deserve respect. The officer wasn't yelling at all of the kids, just the little smart-mouthed one.