There's a strong correlation between black and being poor, and perhaps the solution is not to create a divide by race, but rather by socioeconomic status. A lot of problems we have today, faced both by black people and poor people alike, can be solved by addressing the problems in poor neighbourhoods.
Of course that is not to say all black people are poor, that would be ridiculous. But in the mind of someone who thinks in a certain way, because a person is black it means that they are in fact more likely to be from a poorer family, may have received lesser education, etc. So I think socioeconomic status is a much more fair and less divisive way grouping people.
"All lives matter" is certainly reactionary, but I think there's truth to the idea the BLM isn't the correct way to solve the problem.