I fundamentally agree with your broad point. But the core of the BLM movement is more generally about a longstanding hostility towards black people in the CJ system. We know the Nixon administration began the war on drugs in part as a way to punish urban blacks. That's on record. We know the war on drugs has been used as a cudgel against poor black communities for decades. Black communities did not have anything close to the level of crime (violent or otherwise) before the crippling policies of the war on poverty and the war on drugs took hold.
Moreover, the war on drugs is still - as of this week - a bipartisan supported effort.
Our police also kill many white people (more white people than black people - another fact not mentioned in the MSM) and by and large, the victims of police violence do have something in common, but it's not their race.
It is their gender, primarily. Income level is another common denominator. As you point out, another commonality is whether someone is armed when the police show up.
If you're a poor man in a poor area and you're armed when the police show up - that's the recipe for getting killed.
The stats are all in this paper published by the World Socialist Website, of all places.
An insightful quote: "This data may seem surprising, but it gives credence to the perspective that the focus of many of the most recent high profile police shootings was in large urban centers where blacks were the victims. Poor whites are in essence invisible to the national discussion on police killings. What the present data show is that what whites and blacks who are killed by police have in common is poverty. "
