Edit: Ouch, looks like quite a few people here do. Do y'all really think that's the best way to effect social and political change? A minority of Americans screaming louder and using terrorism to vent their spleens won't solve the issue. In a democracy, everyone must focus on getting more people to vote for different policies to effect change.
If it makes you feel a little better about the world, I downvoted you because I thought you were wrong that no one supports this, not at all because I support burning police cars. I've definitely seen lots of support online that accepts the destruction of police (aka public) property as a legitimate (or at least expected) form of protest, and am surprised that you haven't. So yes, there are supporters, but possibly not quite as many as it would first appear.