If you feel tempted to turn away from or condemn resistance as a whole because some people are resorting to property destruction and violence, I suggest you read these words of MLK himself on the topic of rioting:
"Now I wanted to say something about the fact that we have lived over these last two or three summers with agony and we have seen our cities going up in flames. And I would be the first to say that I am still committed to militant, powerful, massive, non-violence as the most potent weapon in grappling with the problem from a direct action point of view. I'm absolutely convinced that a riot merely intensifies the fears of the white community while relieving the guilt. And I feel that we must always work with an effective, powerful weapon and method that brings about tangible results. But it is not enough for me to stand before you tonight and condemn riots. It would be morally irresponsible for me to do that without, at the same time, condemning the contingent, intolerable conditions that exist in our society. These conditions are the things that cause individuals to feel that they have no other alternative than to engage in violent rebellions to get attention. And I must say tonight that a riot is the language of the unheard. And what is it America has failed to hear? It has failed to hear that the plight of the negro poor has worsened over the last twelve or fifteen years. It has failed to hear that the promises of freedom and justice have not been met. And it has failed to hear that large segments of white society are more concerned about tranquility and the status quo than about justice and humanity." (Emphasis mine)
Realize that it is a symptom, and address the root cause. Violence sucks, and when there is no justice to the point that the unheard have to resort to it for attention, catching civilians in the middle of it, something already should have been done a long time ago. I'm quoting a bit more here than some may quote to make it sound like an endorsement of destruction, which it absolutely is not. But I want to make it clear that it is morally irresponsible, and I would go so far as to say not even moral at all, to condemn only the protesters actions in these situations. I won't condemn the one without condemning the other in the same breath. Police can do a lot more to prevent riots than they can to control them. Start by putting processes in place by which cops that murder citizens are truly held accountable. If real progress is made on this issue, riots will evaporate.