Call it what you will; it is the truth. What this really indicates is that no matter what progress is made, what reparations are made, what concessions are given, what biased considerations are given, the left and a lot of this country actually believes in the perpetual 'downtroddenness' of blacks. It should be enough to make ANY black person feel ashamed.
Democrats want to keep Blacks voting solid Democrat (they are their most loyal group).
Primarying Obama will weaken that grip, possibly forever, for Democrats. Many Blacks will feel betrayed.
Therefore, Dems can’t primary Obama out of fear of losing the Black vote.