It is the human tendency to deny the reality of "conspiracy", even though all of human interaction is by definition a "conspiracy". Conspirators rely on this habit of denial, because it makes their conspiracies possible. As long as people are denying that conspiring is possible, then conspiring is guaranteed to be successful.
"Nobody would do that. Nobody would even think of doing that."
The credo of the most successful conspirators is this: "Make what you do so far removed from normal thinking that normal thinkers would never even consider it possible."
People in general do not feel happy about intrigue and conspiracy. They want to live their lives in peace, without worry. They want to be able to put their bag down, and attend to other business, without worrying that someone will steal their bag while they are otherwise involved.
The true Conspirators are by now so far ahead of commonplace thinking that what they are aiming at is not stealing the bag, but replacing it with their own bag, and telling you it's the one you just set down.
People are too easy to control.