Evil

If evil geniuses are so rare, why do so many bad people get away with so many crimes against their fellow citizens and, when they become leaders of nations, against humanity?

According to Burke:
The only thing necessary for the triumph of evil is for good men to do nothing.

Append to that:
It is also essential that good men and women not be educated and propeganderized into believing that real evil is a myth and that all malevolent behaviour is merely the result of a broken home or a failed society's shortcomings, amenable to cure counseling and by application of a new economic theory.

And not forgetting:
the greatest trick The Devil ever played on the world was convincing mankind that he didn't exist.