If Carson does not offer the things a voter wants, and Hillary does, then that vote more than likely goes to Hillary
If Hillary does not offer the things a voter wants, and Carson does, then that vote more than likely goes to Carson.
If neither do not offer the things a voter wants, and there is no third option, then that vote may not be cast, goes to the party the voter normally favors, or go to a third party vote, etc...other.
It is not hard to figure out. Of course two GOP narratives are in competition here--"Do Blacks vote for blacks based on their skin color?" versus "Do Blacks only vote for Democrats?"
I don't see this as the GOP narrative at all. Either of your examples.
Blacks are individuals. They all have different brains. They think differently, prefer different things, have different ideas, don't necessarily like fried chicken and watermelon...or... maybe they do? There is not a stereotype we can apply to all blacks because their skin pigment is darker than others. This is quite simply, ignorance.
As a voting demographic, the black vote favors Democrat candidates historically. It's because the Democrats actively promote programs (free stuff) specifically targeted to the black community. Marketing 101. It doesn't matter that the programs never come to fruition or if they do, they don't work as promised, or they haven't changed the economic prosperity of blacks in any meaningful way since 1965.... all that can be rolled into a spitwad and blown at the mean old republicans who you can "never trust" because your daddy and granddaddy said so!
But you know... I see LOTS of examples of black conservatives lately. More and more, blacks are realizing how the Democrat party has duped them, exploited them, lied to them, and led them down this path of perpetual dependency, away from their true potential.