Self-deception, my silly apes, is likely the main reason for the spread of misinformation.

You have all been taught; especially as children, that people who lie to others are not to be trusted, and while this holds true; it’s those who lie to themselves that should cause you greater apprehension.
Self-deceivers are either incapable or unwilling to hold on to the more abstract qualities of truth, thus are often reluctant to entertain facts they find inconvenient to their narratives, or to have the difficult conversations needed to move forward.
Misinformation
Worst, their lies (to themselves, as they are about their own characters and behaviour) determine their self-worth, their own perceived value, which is invariably low, and easily purchased by people who see it the same. They will almost always move towards environments where their characters are validated but never challenged. They are easily manipulated; they are a viable tool in the manipulation of others.
Their conduct is a fraud made more perverse by the permission the rest of society gives them to continue to self-deceive.
Again, they are the people who happily push and peddle misinformation.
— The Devil Unbound.