Without putting words in their mouth, I think they are arguing that in the US, one’s skin color plays a larger role than their behavior, when it comes to whether their interaction with the police results in brutality or not. While they are both factors, one is a stronger predictor than the other.
If I’m pulled over while being white and I cooperate, I’m probably getting the ticket and going on my way. Worst case the cop is having a bad day and wants to escalate, they arrest me for something. If I’m black, worst case I’m going to the morgue. Average case is going to be worse if I’m black, all other things (including my attitude) being equal.