During the OJ trial, the prosecution dragged the jury to OJ's house, because they wanted the jury to see that OJ had more in common with whites than blacks--for example, his wall was full of pictures of the rich and famous, with hardly a black face among them. Surprise! Cochran and company had thought of that, and they filled the walls with pictures of black people, and as an added touch put a Bible on his night-stand.
Perhaps Nagin finds it as hard to relate to real black people in the same way that Howard Dean couldn't relate to southerners, when he claimed that his party would be the party of southerners with confederate flags on their pickups. Similarly, Nagin is essentially promising his constituents "fried chicken on every plate," not realizing that they aren't as motivated as he'd imagined by a love of fried chicken.
Not that well articulated, maybe, but an interesting thought. Maybe he's out of touch with people who can't buy a fancy house in Houston the day after the disaster.
Actually, many black Americans feel that elitist political Democratic blacks are the same or worse as whites they "think" are racist. They just don't know who or what to identify with and support. From my perspective, you've expressed sentiment that is felt in an easy to understand way.