If you're being violent, destroying property, smashing windows, throwing bricks and burning down buildings, then you are a thug. You being black doesn't mean you get to be called something different. Were the officers behind the unjustified murders thugs? Yes. But you don't get to curse out pigs while rolling in the slop with them. I'm not gonna sit back and act like what they're doing isn't wrong just because they're black or because of the catalyst that sparked this reaction.
Having a riot is the equivalent to throwing a temper tantrum. Even if the cause and the way you feel is justified, what you're doing is gonna overshadow that in the long run. It makes harder for the people you're trying to get attention of to see it from your side. If you're burning down buildings, and destroying property, that's what they're gonna see. The concern is gonna become "How do I stop these people from damaging themselves, others, and the city any further" rather than "Now that's a good argument and outlook on police brutality, we should think about this and work towards solutions."
You cannot make someone acknowledge and work towards a problem by creating and throwing another problem in their face.