The problem with an article like this by Maggie Koerth-Baker is that it attempts to lump together all conspiracy theories in the same bucket. Somewhat akin to making a statement that there is only one religion in the world, something that clearly is not the case. Conspiracy theories can have many origins; they can originate from fear or ignorance while others develop from well founded hypotheses that are based on strong circumstantial evidence.
Jesse Walker who writes for reason.com puts a better perspective on the article:
Virtually everyone who has any political beliefs at all believes in at least one conspiracy theory. Imagining conspiracies is just part of how human beings tend to perceive the world: It's where our drive to find patterns meets our capacity for being suspicious, particularly when we're dealing with other nations, factions, subcultures, or layers of the social hierarchy. This habit manifests itself across the political spectrum, and it always has. And it is intensified by the fact that conspiracies, unlike many of the monsters that haunt us, do sometimes actually exist. (Koerth-Baker acknowledges that last point -- she mentions Watergate, Iran-contra, and the Tuskegee experiment -- so presumably when she writes "political conspiracy theory" she means "political conspiracy theory that is not accepted historical fact.")
