I am reminded of the saying in MIB.
There's always an Arquillian Battle Cruiser, or a Corillian Death Ray, or an intergalactic plague that is about to wipe out all life on this miserable little planet, and the only way these people can get on with their happy lives is that they Do... Not... Know about it!
People don't want reality or the truth, they want to be told they look good in there tight spandex pants, all 400 pounds of them. They want to all just sit around eating bonbons and think no one will do anything to us, and the government is a big conspiracy to make their lives miserable.