Kurt Vonnegut wrote a fascinating book called Mother Night. It's about an American who works as a Nazi propaganda minister, who believes he's on an undercover mission for the Allies. It's never really clear whether his employment by the good guys is real or imagined, and by the end of the novel he comes to the conclusion that it doesn't really matter, because he's guilty of war crimes either way. Vonnegut wrote that the moral of the story is, "we are what we pretend to be, so we must be careful about what we pretend to be". It's a good moral.
Why do I bring this up? Because obviously Jon Stewart never read Mother Night. Check the link out, they've got a video.
The Readers' Digest version is that Stewart thinks Crossfire is a let-down, that they fall through on their responsibility to foster real political debate. He accuses them of being party hacks, of not forcing politicians to answer the tough questions - but he has no good answer when the subject of his not-even-softball interview with Kerry comes up, and he seems flabbergasted and indignant that the program's hosts won't take him seriously.
I've got news for you, Jon: If a presidential candidate is on your show, and you've sent people to the conventions, and you've published a book, well: you're a real news show. The prank-calling puppets are an excuse, and a poor one at that; If you sit behind a desk and ask Kerry how he's been instead of asking him a real question, you are a monkey, and it doesn't matter what network you're on.