The Democratic party in this country has (as all conservatives already know) been taking the black vote for granted since sometime around the early Bronze Age. Wasn't there some fuss, just a few months ago, regarding Nancy "The Mummy Returns" Pelosi assuming her House leadership position by ruthlessly squashing some black congressguy who got in her way, or somesuch? (I may be completely misremembering the salient details, here. Feel free to correct me, if I'm in gross error here.)
Black voters have no one to blame but themselves for this unhappy status quo, ultimately. When a woman keeps going back and going back and going back to the man who beats her, knowing full well that he's likely to beat on her again, in the not-too-distant future... that's not assault any longer. That's masochism.
You make a good point. Blacks have been convinced by their self-appointed leaders that it is the Republicans who would "keep them on the back of the bus". But times are changing in this information age with the internet and Fox News. It also helps that Jesse Jackson has lost a great deal of his moral high ground and credibility with his infidelity. I don't think blacks objected to Jackson's blackmail of major corporations, having been convinced by Jackson, et al that it was their due, a form of pay-back for past wrongs. But the more they learn about his millionaire lifestyle and the child he fathered with his mistress, the more disillusioned some have become.
So there is hope that those who choose to educate themselves about political matters will eventually realize that the DemonRats are not their saviour, that welfare is the plantation that the DemonRats strive to keep them on to maintain their power.