Crushing Gibroneys Is My Business. And Business Is Good.

Fat guy talks alot about the need to present evidence, but other than simply accepting and parroting the government's official story, he fails utterly to present any evidence of his own. He doesn't seem to grasp the fact that both he and the guest are positing conspiracy theories, just different conspiracy theories. Because of this fact, it is unfair of him to demand evidence from the guest without equally demanding it of himself.

One can disprove the government's official story without posing an alternative theory at all.  This is called ruling possibilities out, and it is a common practice of criminal investigators and law enforcement. Basically, Fatty is saying that unless one has a fully developed alternative explanation for events, one has no right at all to approach the government's explanation with skepticism. This is counterintuitive since obviously one would have to realize the discrepancies in the official account before even acknowledging a NEED to pose an alternative.