please understand i'm not trying to justify what the police did, not in any way, shape or form.
however, i understand their frustration when a suspect won't cooperate. my point is that if the police are trying to arrest you, don't resist. so many of these stories involve a suspect that wouldn't cooperate (like way long ago with rodney king). it can set off some police officers in a final straw sort of way it seems.
i don't think the police are deliberately looking to use harsh measures to subdue most/every/any suspect, but i think when a suspect resists, it exacerbates the situation.