It's irrelevant, most murders are factually intraracial and not between different races, so there probably is a higher rate of whites killing whites than cops murdering whites, and a higher rate of blacks murdering blacks than cops murdering blacks. It's a huge strawman to use that as an excuse - Blacks killing blacks happens the same way most whites are killed by other whites, it's two different issues altogether.
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you