My answer is here to prevent a thread drift.
Black lives indeed do matter. Not the ones being shot daily in Chicago's less desireable environs, and definitely not the black cops in uniform .The lives which matter to the folks in power and in the media are the middle class voters,who are sold a collateralized and innaccurate picture of the world.Its the "Truman Show", writ large and without the cameras.
In some ways, the plight of the North Korean and the typical Chicago resident are frighteningly similar. Both individuals are told by the information sources around them that the world is X, when in fact its Y. Dead Africans doesnt fit into the "Truman Show Bubble" of racist cops and evil gun owners, so its left out of the artifical media environment with the certainty of a North Korean censor. Dead black criminals , however, can be neatly integrated into the "Truman Show" of American media fairly easily, if one omits some minor facts about who the real aggresor was.