The point is that, for largely existing political coalition reasons, people are trying to make a class problem be about race because it makes it align with the base of a particular political party. Police unions lean Republican, so Republicans have a political need to defend them, so if you can pit black people against the police then you can get them to vote the way you want without actually giving them anything. And then you don't have to worry about them getting together with poor white people to ask why housing costs so much and there isn't more economic opportunity for non-megacorps.