Michael ("Big Mike") Brown's conduct was an extreme departure from the "politeness" toward police which you recommend.No where did I say the police are above the law. I simply offered common sense advise on how to deal with encounters with them, it's never failed me. You don't have to follow it, then you might end up like Michael Brown, he had a lets get tough with the cops attitude.
I agree with your advice to be polite in encounters with police -- but only when the police conduct calls for reciprocal politeness. Otherwise a polite response to an unnecessarily oppressive or offensive demeanor amounts to slavish subservience which far too many contemporary cops seem to expect (See, COPS, the tv "ride-along" documentary series).
Unfortunately too many cops are inclined fabricate charges against subjects who fail to behave subserviently toward them, a fact which to a significant extent has much to do with the presently emerging anti-police atmosphere.
I'm not suggesting that all or most cops are guilty of arrogant and/or generally rude conduct toward the public, but enough of them are to have alienated a substantial number of individuals who can recall having unpleasant encounters with nasty cops. And all it takes is one such encounter to form a lasting impression.
Just another example of why you politely comply regardless of the cops attitude, then you take it up with the department if need be. The police in the small town I live near have a very bad reputation if you go by what people say, yet in my few encounters with them I have seen nothing but professionalism and a generally good attitude.