I believe you're correct in regards to some cases. In others, race is the deciding factor. If a person assaults or attempts to assault a cop, that's just asking to get shot, regardless of the perp's race. However, when the perp is white, statistics indicate that cops will hold their fire more often and try to reconcile the situation without shooting the perp.

I don't think it's that complicated. A white cop is more likely to identify consciously or subconsciously with a white perp than with a black perp. Take a sample of one thousand perps, and cops are more scared of what a black perp might do than they are of a white perp. It's the reptilian brain at work. "That white perp is from my tribe; I'll wait and try to learn more before taking forceful or lethal action." That black perp is from another tribe; I already don't trust him; I'm not gonna' take any chances; Oh sh!t he's reaching for a gun - I think - so pull the trigger now before it's too late (for me, that is).

Personally, and logically, I have no issue with a cop of any race shooting a perp of any race who actually poses a clear and present danger (not an imaginary danger) to the cop or others. I take issue with events where cops shoot perps who are unarmed and clearly pose no direct threat, like shooting black perps in the back while they are running away. When was the last time you heard of a white perp being shot in the back while running or attempting to run away? Like maybe never?