Law enforcement has a cultural problem that needs addressing but getting rid of law enforcement entirely or blaming all law enforcement equally are absurd notions.
Have you made the case that Mike Brown didn't warrant getting shot? No.
Point is Mike Brown is an edge case that easily falls on the other side of the line not knowing the facts the grand juries has. There are plenty of cases where rioting is actually warranted (regardless of an officer being disciplined or not). The fist video in this thread or even this one:
I can find many videos showing law enforcement has been trained or acts in such a manner that is unacceptable and may require wholesale firing and starting over again.
Fact is treat law enforcement like dangerous animals to be avoided and engaged in such a manner to appease their inflated sense of self worth until you can complain and challenge in a mediated situation. Record, preferably surreptitiously, all encounters with law enforcement. Put cameras and microphones on your car.
Generally you should not resist arrest. It is against the law. The time to challenge the arrest is in front of a judge.