In my experience a good number of the people caught in "police brutality" issues tend to have had run-ins w/ the police prior. Mr. King has has something like another 11 convictions of various types since 1991, and was on parole at the time he ran from police.
Had he simply pulled over and not acted like a freak, he likely wouldn't have been beaten.
The basic precept of such riots is pretty much poverty. It ends up being the poor abusing the poor while the not-so-poor look on from behind the safety of police barricades and gated neighborhoods who shake their heads and say, "Oh it's such a shame."
But, it comes down to money and an inability to empathize with others. When you're poor enough to have little to lose, you cannot empathize with those you are ultimately stealing from. Even if they have less than you.