John Stewart, John Yoo and the implications of duty.

As long as we're on the subject of John Stewart, he had John Yoo (the Bush admin, lawyer who defined torture/waterboarding and what not) on the program. Here's the question:

Assuming he believes that Yoo's action lead to torture, does John Stewart have a duty (in the ethical sense) to confront Yoo?

Or is he just a comedian?

And what are your thoughts on the interview?
Part 1