What's wrong with NBC for keeping Imus on tv? The show is out of control.
The simple reason is that they get no ratings in those hours, anyway, so turning on a couple of cameras while Imus does his radio show is cheap product. Also, there is no public indignation over Imus. He's such a smarmy kiss-ass to Senators of both parties that he covers the bases. Imus is a very "inside the beltway" phenom--he's the radio host DC puppet heads think is cool, for some reason.