The second is that of basic causality. If economic circumstance and barriers to things like wellbeing, quality of life, and well, things like the very obvious existence of racism (please do ask me if you'd like me to evidence that for the UK) . . . then any attacks made by minorities in any disproportionate manner to their demographics size is simply a symptom. Much like how people are defending the "concerns" that these riots apparently suggest.
It can't be had both ways. If these "concerns" are in any way legitimate, so are the things that drive people to violent excess. No? Even if the reaction is inappropriate or outright criminal, assuming the justice system itself is being applied fairly, etc, et al.