Chris Wallace says he just doesn't understand the difference between Fox News' activism and the type of material presented by Comedy Central's Jon Stewart.

Stewart tried to spell out the differences Sunday when he appeared on the conservative network but Wallace just didn't seem to get it.

Wallace accused Stewart of playing politics by comparing a video for former Republican vice presidential candidate Sarah Palin's bus tour to a herpes medication ad.

"You're insane," Stewart charged. "Here is the difference between you and I. I'm a comedian first. My comedy is informed by an ideological background. No question about that. The thing that you will never understand and things that conservative activists will never understand is Hollywood, yeah, they're liberal. But that's not their primary motivating force. I'm not an activist. I'm a comedian."