In fact Russian ‘racism’ is very different.
You can easily see Jews and a lot of Asians among rioters.
Russian society is both race and gender blind.
It is mostly cultural. They don’t like brown muslim people since they don’t mix with major population and setting troubles on their Southern border.
In this particular reason there were a few of violent crimes committed by muslim immigrants attracted attention nationwide in Russia. Authorities has failed to investigate it out of PC reason so the riots happen.