[shawmutt]

As I understand it, conspiracies are believed for a modicum of control. A "theory" of an evil government plot is somehow less scary than random violent events.

Unfortunately, the weaving of a conspiracy theory is very complex. Like Isherwood was saying, as evidence is brought against the conspiracy, the conspiracy gets more complex to support the conspiracy, not the reality. It starts with a small government plot involving a few conspirators. By the time all the kinks of the conspiracy are "figured out", hundreds if not thousands of people are all part of the conspiracy! The "theory" falls flat by the sheer mass of people required to make the conspiracy reality.