Yeah, I think Ian thought the guy was the real deal and didn't want to take the chance his listeners would think the guest was smarter/deeper than he was. He kept looking for opportunities to score points and one up the guy with his questions, but he never layed a glove on him. He didn't realize initially the guy was clueless and stringing words together as if using some nailing-jello-to-the-wall buzz phrase generator.
The whole thing reminded me of the chess guru who thought I was an equally capable player. Once he realized I was totally inept, he dispatched me in nothing flat.