I disagree, Bob. I don’t think that just because the audience cheered it means that they believe this theory, they just thought it was a witty joke, and were enjoying Chris’ little rant about the medical system. That doesn’t mean people don’t believe in conspiracy theories, but you seemed to be saying that the entire audience believed this theory.
Although it’s not exactly a strong link between coke and AIDS, I would go with JohnM’s theory about long distance truckers.