That episode had Republican U.S. House Rep Darrell Issa.
John Phillips Avlon, author of Independent Nation: How Centrists Can Change American Politics and Wingnuts: How the Lunatic Fringe is Hijacking America was on the panel in that episode as well. But I know, to you centrists are the lunatic fringe left.
Also on the panel was S. E. Cupp, author of such liberal propaganda books as Losing Our Religion: The Liberal Media's Attack on Christianity and co-author of Why You're Wrong About the Right.
This is not uncommon. There's usually a pretty even balance of "left" and "right" on the panel. The audience is left as hell, and very rarely cheers for a good point made by a conservative, and Maher himself is pretty far out there on the left with 99% of his positions. This much is true. But they let the conservatives speak, and most of the time it doesn't get "shouty" or "pushy" at all. Now if they had Tim James on there, for example, you're right, he'd probably get laughed off the stage, but that's for good reason, in my opinion.