They assume that because it is very common knowledge that having police interactions while being black is often more dangerous than it needs to be.
Having raised a black son, I have first hand experience with this, and the police interaction differences from my white sone are stark, significant and very easily seen.
Sure, one event can be debatable. Where people actually remember the past, you know, pay attention in some meaningful way, that event may well serve as a catalyst to move people toward greater recognition and potential remedies.
I find it very notable how these last few shooting events saw people go to extremes to grant consideration to the person holding a gun. Generally those break down along authoritarian lines too.