[Oprah] seemed to be mimicking, through a sort of mock-wimpy intonation, those (mostly white elite?) feminists who were shocked about her endorsement of Obama. And then she started rousing the crowd in a sort of loud faux-gospel mode, answering to her critics that she was "a free woman!" and then went more into the edgy Jesse Jackson type old-time campaigning style.
The problem with all that is that she created her $1 billion empire precisely by appealing to a mostly staid white suburban therapeutic audience, to whom she is used to talking in precisely the same flat-toned neutral manner that she was this weekend apparently mocking.
So what I hear Vic saying is that, having built a media empire by talking white, it's no good for Oprah to go "blacking it up" now. (This is the point at which I double over, feigning acute appendicitis, in order to flee the room, warning other partygoers to avoid, by all means, the guy in the toga.) In contrast, when Yalie rich kid George W. Bush goes into his Boomhauer schtick, pretending to talk in the style of the working folks his economic policies are screwing, he's just being "authentic."