Stop motion video with Mear One painting a thought provoking mural in London Sept 2012. Sparking conversation and debate ... − YouTube
The powers-that-be obviously work very hard to control public perception and understanding of news and historical events. The "conspiracy theory" meme − that it is only a tiny, dangerous fringe element who attempt to pull back the curtain and reveal various nefarious schemes − has been valuable to the power elite who wish to remain essentially hidden.
Individuals are less likely to pursue answers if convinced they are the only ones with questions. Most people don't want to be among the minority, disrespected, or considered unpatriotic, let alone "crazy." It is presumed safer (easier?) to push aside any nagging uncertainty and remain reliant upon the state to keep one safe and secure from the bogeyman du jour.