I got two letters from black cops, who said that when they enforced the law in black neighborhoods, they were accused of selling out, of being Uncle Toms. But the angriest mail came from blacks who weren't cops. The thrust was that cops single out blacks, pick on them, harass them, and refuse to enforce the law evenhandedly. Rationally this might be debated on any number of grounds. It doesn't matter.
Blacks believe, believe deeply, that they are victims of the police.
For them, this isn't debatable, can barely be discussed. The sense of grievance is so nearly universal as to approach the predictability of gravitation. They are very angry about it. Not all of these letters are angry, though. Some are almost pleading.