Do you not believe that the BLM protesters have a legitimate grievance? Black males are clearly shot at a disproportionate rate to their presence in society.
It may be that the difference is entirely explained by African Americans being generally poorer and living in higher crime areas. However if this is so surely it would be pretty easy to show that for any category of police call out, say "man acting suspicious" there is no disparity in whether they end up in the morgue or not - there is very little independent data to prove that.
There is however an awful lot of data that suggests African Americans are treated substantially worse than white Americans in a whole host of other criminal justice fields (# traffic stops, #searches, police use of force, arrest rate for pot etc etc etc).
Even if you take the position that there is little to no racial element in police shootings, it has publicized an issue that really had very little attention - people in America of all races get shot at a very high rate compared to their Western counterparts.
BLM has encouraged discussion on a whole range issues such as community policing, whether stop and frisk is effective, how data about shootings is collected and by whom, police body cameras, if police mistakes are made whether lessons are learnt and the officers punished etc. All these are worthy of debate and analysis and should lead to better law enforcement for all regardless of the initial reason the issues were brought up.