As I said, the guy was probably not trained iin the martial art of bike chain, but the cops were trained in take down. "Overkill" seems to be an understatement here. Why didn't they run over him several times with a unit, too, while they were at it?
Besides, I did not post the topic as a comment on the legality of what the cops did. I am pointing out that the jerks aren't trained well, or simply have despicable attitudes or both.
"Shyte! The guy gave us the finger. And he's got a stapler (or bike chain, or pencil, pair of chopsticks, or....) Ventilate him, boys!"