Stop caricaturing themselves. The right has made it very clear that there is no more room for a moderate or a "regular" black republican. Guys like JC Watts and Michael Steele have essentially been run out of the party and replaced with far right black republicans who seem bent on using their blackness to say things a white person wouldn't be able to get away with. Allen West, Alan Keyes, Hermain Cain, and others are in a constant battle of escalation: who can go the farthest to denigrate Barack Obama, or the black community, or both. Even Ben Carson, who on the surface seems like he would be a more traditional black republican, has decided to follow this path.
Liberalism and conservatism are largely based on one's economic views, and what role the government should play. It has nothing to do with race, and therefore there is nothing "wrong" with a black person being a republican. I think republicans could have an opportunity to win over some black people if they weren't so invested in denigrating black people, and trotting out black republicans to denigrate black people even further.
Ultimately, minorities in the US have always voted in their best economic interest. When Irish people first came to the US they were treated like shyt, especially by republican party bosses on the east coast. Eventually they gravitated towards the democrat party because they actively pursued their support, and decades later JFK came around and solidified them as democrats.
Likewise when Lincoln freed the slaves, black people began voting universally republican. But that slowly started to change after the Great Mississippi Flood of 1927: soon to be (republican) president Herbert Hoover was in charge of cleaning up the flood, and made many promises to the black community most impacted. He was elected a year later with large black support, but over the course of his presidency he didn't follow through on his promises. The black vote began moving to the left in 1932 with FDR, and was fully secured in 1964 with the passage of the Civil Rights Act.
Ultimately the republican party has made a very blatant gamble on the white vote. They seem to believe that this "us vs them/makes vs takers" stuff is going to propel them back into the White House. The problem is that the white vote is shrinking every 4 years. Meanwhile about 10k Hispanics turn 18 every day in this country. Obama crushed Romney last year and gave a preview of what electoral college politics will look like in the future unless republicans change. They cannot win the presidency unless they start winning over Hispanics, and blacks. They don't need to win the black vote, they just need 10-15% in certain areas of the country (Ohio).
Remember this?
Rove's argument was that there were still white counties that hadn't been counted, and they would win the state for Romney. The problem was that the remaining uncounted black vote in the Cleveland area was so large that it didn't matter.
Now you know why republicans are fighting their hardest to restrict voting rights. And why they're trotting out black republicans to defend this shyt.