Let me clear up what may be the confusion between ICB and myself with regards to Sharpton "speaking for" the black community at large.
When I say that I believe he does, it is because he echoes the frustration a lot of blacks have, as evidenced by ample accounts of discrimination in society (I can't even call them "remnants," because they're so strong and consistent everywhere), and by virtue of the sorts of social problems, at the structural level (government, education, racial attitudes), that they seem to share.
So, when I say Sharpton speaks for the black community, I mean it.
OTOH, I do not believe he speaks *everything* for the black community. Perhaps this is the source of your frustration? He does not hold blacks accountable for very much. He may well do so, but he does it privately. It's an interesting omission that makes it easy to discredit everything he says and does.
The missing portion of his narrative is, I think, best summarized by the sorts of things Bill Cosby got in hot water for saying. Cosby became outspoken at his frustrations of inner-city black culture, of their rejection of proper social norms, their embracing of low interest in proper education, a lack of achievement orientation, and so on and so forth. Plenty of the kinds of books where you'll find plenty of blacks lamenting how society still discriminates against them (the works of William Julius Wilson, Elijah Anderson, and Katherine Newman to name a few) also contain the very same people lamenting that the culture of inner-city blacks has made the "poor culture versus social structure" argument a chicken-and-egg scenario in terms of policy. Will throwing money on education help a community disinterested in education better themselves? Will ending welfare change a culture that has little to no resources to better themselves?
Focusing on only repairing one social ill isn't going to make anything better, in short.
I would argue that Cosby and Sharpton are two halves to a complete narrative of the kinds of attitudes many blacks have in the current era - it's complex and sometimes contradictory. That's never stopped anybody else before in terms of political attitudes.
Cosby was lambasted by others, I believe, not for his content but for his conduct. He was Heathcliff Huxtable to many, the Jell-O pudding guy to others...someone who, in their entire public career, *never* tackled any racial topics head on. All of a sudden he blows up and turns into the "what the hell is the matter with all you people?" kind of character. While many people agree with him, it was his sudden and accusatory demeanor, along with his career-long silence on race issues, that made people fail to take him seriously. (there's also a potential for backlash because of anger at him for "airing dirty laundry" - he didn't say anything blacks don't know, but it didn't do anything to help their average situation; I suppose you could parallel it with the Dixie Chicks controversy - the content of what they said was never under question, but the context of where and how they said it ruined any potential impact it would have had)
So, long story short, I agree with the sorts of things Cosby said, and only wish that he didn't sound like such a grade-A asshole when saying them. I think the ideal person who would "speak for black America" would combine the calling-out of racism in society of Sharpton along with Cosby's emphasis on introspection (though, of course, turning it on its head into a more hopeful and positive approach, rather than a major-league scolding). Barack Obama has a lot of these characteristics - but he is not a perfect being. It's hard to hold these two narratives down simultaneously - even if they can both be true, if you use the wrong narrative in response to the wrong situation - say in response to the Imus situation - well, the results would make Imus look like he got off light, IMO.
That's my clarification - Sharpton doesn't say *everything* for the black community, but, rather, has a direct and consistent, but *partial*, narrative that speaks to the black experience. His willful avoidance of the other half of that narrative is troubling and disappointin, but does not discount the content of what it is that he does say and argue.