They were defending their viewers, whom O'Reilly had publically insulted. They weren't defending the seriousness of their programming(at least, not in this case). If your fanbase was attacked, wouldn't you defend them?
I think when any cult show starts to climb into mainstream consciousness, it's inevitable that they're going to start thinking of themselves on a higher level than they did before. It's unavoidable. That being said, as an avid fan of the show, I don't think their agenda has changed at all in the last four or five years. They do have a slightly leftist slant(a fact they don't hide, and infact make fun of), but there's clearly no punches pulled. They'll satirize anything and everything worth satirizing, and they usually do it extraordinarily well.
