A very reasonable idea. However, my point was that if you have an "attack" on a white neighborhood, and the police act ineffectually (or even if it is just perceived so), what do you suppose the residents would do?
I'm not sure any neighborhood (I'm over the river in Kentucky) around here is so cohesive that they could instantly form a force to fight back. Surely, a few individuals with guns would fight but many would cower in their houses. If we are talking about more than a handful of rioters, a police force would be necessary.
My wife bought me my first firearm shortly after the LA riots, where we saw the cops running away from the rioters.
Look at it from the cops perspective: if they start shooting rioters to protect white homeowners, they risk being charged and jailed, or at least being fired and losing their pensions. If they "show restraint" and stand around, or suddenly find other places they should be, they do not subject themselves to any personal risk. Better yet, in a riot situation, they would be strongly tempted to go home and protect their OWN homes and families.
A cop is just a civil service worker who wears a badge and gunbelt.