Blitzer didn't think up the term on his own. He had a tweet from Rupert Murdoch: "Ben and Candy Carson terrific. What about a real black President who can properly address the racial divide?"
How did Carson do? Of course, he maintained his utterly unchangeable calm demeanor. Carson's answers included: 1. Murdoch is entitled to his opinion, 2. I don't want to talk about it, 3. It's just "semantics," 4. I don't like political correctness, 5. Obama is the president and he is black, and 6. Murdock was trying to say that a "real black President" would be someone who "really elevated the black community," and Obama hasn't done that.
#6 is the substantive answer, but it's carefully attributed to Murdock. Blitzer, for all his dogged re-questioning, failed to ask the substantive question. I think Blitzer was focused on trying to trap Carson into embracing the concept that of being a "real" black and denying Obama that status (which harkens back to the old "Is Obama black enough?" debate of the 2008 campaign).
Blitzer could have taken the inquiry in a more substantive direction and asked: Do you think that people voted for Obama because they were inspired by the idea of having a black President and that idea meant something important about what would happen as a result of having a black President, something that has not occurred? If yes, do you think that idea still has meaning and that the effect could occur if we had a different black President or do you think it was delusional and people should get beyond attributing meaning to the race of the President?