I have friends in the USA who believe the country is still inherently racist.
If you give racists guns and a badge which grants authority to kill people, it is likely some of them will manipulate a situation to a point where they feel they can justify the use of extreme force, then explain it in a plausible way.
Then, within the organisation, it only takes a few higher ranking racists to turn the other cheek and hey presto, you get the policing system we see in some US states
I find the USA quite scary. In the south it is like watching a crowd of people with the mental capacity of a school child, and all of them own and carry guns.
At our friends house a fight broke out, and I mean a real fight over the dinner table because one guy said gays were unholy, and the other disagreed. Luckily, they were brothers. Otherwise I foresee one of them going for a weapon at some point, and out there in the countryside, nobody would find the body.