I don't find anything particularly surprising or relevant about Sharptons and Mosely-Brauns numbers. My reasoning is that this is a poll of Dimocats, 95% of blacks are Dimocrats and 95% of blacks vote for blacks, hence the CMB and AS numbers.
Neither can win the nomination nor is it likely either stay in throughout the primaries, so those black votes will be spread among the front runners.
So, when you consider that blacks amount to about 13% of the population and 95% of the blacks vote black when given the opportunity 95% of 13% is 12.3 %...just about the cumulative total of the AS and CMB percentages, it just makes too much sense.
Of course I recognize one little fly in my logical ointment
that is how many of the participants in the poll know that AS and CMB are black?