We wouldn't be having this discussion if all the rioters had done was shout outrage.
I am not saying the rioters do not bear responsibility for their actions. They are acting on false information. That false information was the stone tossed by Newsweek. It initiated a chain of events (ripples) which are subsequently unfolding. Like you said, If I insult a bully's mother, I might set in motion my own subsequent thrashing...