I don't disagree with those characterisations of the reality of violence at all, Jim.
The point I was trying to make is to highlight the acceptance of such a level of violence from 'ordinary' police officers dealing with (what appears to be) a non-threatening problem of public nuisance. The only time I have seen similar over here has been from riot police during a riot.
Anyhow, about to lose my net connection - I hope to return to this later tonight (but no promises).
I would suggest to you that if the police need to use force, it is always a "threatening" problem. Just because he is initially being detained for being a public nuisance, does not mean that he is not dangerous, or even armed.
What I find interesting is that you seem to feel that the police should give a suspect an assumption of compliance. I can tell you now, from psychological studies on the mind-set of officers who have been killed and assaulted in the line of duty, one of the major issues that comes to light is that those officers typically used force later then most of their counterparts, which has a correlation on them being injured or killed.