I gotta disagree a little with this. First, many of the people you refer to escalated the situation a bit with their own actions ... no question. However, I'm not aware of any crime in which the sentence is immediate execution by the police without arrest, representation, trial. You know, due process.
And when you look at BLM, depending on their particular leanings, many will look at the black on black crime and/or Michael Brown and say it isn't an important issue. But, you also have to look at cases like Freddie Gray and the guy shot running away in SC. Particularly in the SC case where the cop tried planting the gun and all of that and the truth only came out when the video emerged. It is ridiculous to think that many of these people in these neighborhoods haven't been victims of this kind of behavior forever. However, there wasn't video before to show the truth, so it was swept under the rug.
Black on black crime is an issue, no question. But it isn't the only one, and one of them is by people sworn to protect and serve.