The race hustlers who now occupy the White House and the DOJ do not care about murdered black kids.
If they did, they would be descending on Chicago where blacks are being murdered by other blacks in staggering numbers.
But Ferguson gets their attention because they gain political capital by charging racism.
Think of it like this: the world yawns when Muslims slaughter other Muslims in the hundreds of thousands. But when Israel fights a defensive war and a small number of Muslim civilians are killed, the left goes totally Jew-hating beserk.
The tactics of the American left are perfectly in tune with IslamoNazis and their Western enablers.