Race war? It will not be Blacks vs White. Whites have lots of allies. It would be Whites, Browns, Asians, and some blacks vs. Blacks and communist radicals.
In many areas the blacks would have to get through the imported rings of non-black foreigners to even reach the receding white populations; gentle giant Michael Brown was stealing from an Asian shopkeeper (and pushed him around) because there were no white shopkeepers anywhere near him to rob.
The couple brandishing guns in their gated community made the news because it seems to be one of the few examples where the miscreants even saw white peoples’ homes. I don’t know anyone who has any incidents anywhere near them.