Tolerance is a concept that has been so completely redefined, that it's very difficult to help people see the difference. A caller to the program recently, a non-Christian, asked why religious people can't be tolerant of secular people like secular people are to Christians. Now, what he meant by this wasn't classical tolerance - show respect for the individual whose ideas you disagree with. He was asking why Christians don't "live and let live" and try to persuade others with different convictions. Essentially, he was asking why Christians can't be moral and religious relativists, just like much of society.
Greg's uses "taking the roof off" tactic in the discussion, and hopefully the caller will continue to think about the discussion and see the difference between true tolerance and what he's asking about. Here's the clip from the program.