Because every time they have a gotcha of some black person dying, evidence quickly comes out to show that he or she bashed a dude's head into the pavement and was not going to let up until one of them was dead/violently robbed a store and charged the cop/had a history of robbing the village and claiming he was just jogging/stashing dead bodies in cars and sleeping with men who shoot at cops/threatened to shoot a pregnant woman in the womb/stole a taser and shot at the cop/tried to steal a pistol and drove away with someone holding onto the door.

Saying "You did violence against this person" quickly gets explained as to what happened. Much easier to just completely throw out all proceeding evidence and experiences and just point at the color on the headstone.