Had It in Holland Park

Obama Says Anti-Cop Rhetoric Can Hurt Black Lives Matter
If you view "them" (whichever them) as the enemy, they will treat you as the enemy.
If you view "them" as your friends and as members of your own community, you can help each other get rid of the bad elements that are poisoning the relationship.

Here is a tip: try turning any bit of anti-police rhetoric on its head: replacing "police" with "black people" and "blacks" with "police." If the black community would find the resulting statement offensive, then the rhetoric is not helpful, it is part of the problem.

eg: Police need to stop killing black people
      Black people need to stop killing police

      Police are racists who target the black community for being black
      Blacks are racists who target white police for being white

      We need to arrest all the bad apples on the police force and put them in jail
      We need to arrest all the bad apples in the black community and put them in jail.

This is not to say any of the statements are untrue - they may or may not be, that is not the point - it is merely a test of whether the statements are helpful in building a better relationship between police and the black community.

If large numbers of the black community disrespect and stereotype police, particularly white police, meeting them with non-cooperation and fear, there can be no end to police stereotyping and fearing the black community. The only hope for a better relationship is for the black community (including Black Lives Matter) to work WITH police rather than against them.  And vice versa: the police need to work WITH the black community, including BLM.