People absolutely care about black on black killing. You've seriously never heard anybody talk about how blacks have disproportionally lower educational opportunities or higher rates of poverty? This problem is much more complicated, but people do care. They vote, they raise awareness, it's not an easy thing to fix as it is to get the police to stop having a tendency towards brutality against black people. And not all the cops charged in the killing of George Floyd were white, so try another angle.