Growing up in SF, I saw this in action. Some of my grandmother's income was earned by keeping a developmentally disabled couple, Steve and Helen Pistone. They were pretty independent but needed someone to make sure they ate and to supervise them. We didn't know that Steve was abusing Helen. One day, Helen was so bruised that my grandmother called the police to investigate their story that Helen was attacked by some young Black men. They couldn't fool the police, and it came out that Steve had gotten angry and beat and dragged Helen off the bus. They had to go; my grandmother would not brook this racist man under her roof. Tellingly, even a cognitively challenged white person had gotten the memo that in American society, Black men were easy targets for blame when a white man -- any white man -- committed a crime.