That's not the point.
The point is, a riot isn't "there's something wrong with blacks" or "thugs" or whomever may be causing the riot. The point is, a riot is the only expression the powerless have against a system where they're being treated in inhumane ways. They're not a sign of protest, they're not started with the goal of change. They're just a sign that the system has failed.
(Provided it's not a bunch of drunk, entitled sports fans, mind you. Those riots are a sign the home team lost.)