In a time of cruelty, Dietrich Bonhoeffer, a pastor, spoke out against the atrocities. He came to believe that the root of the problem was not evil, but stupidity.
Bonhoeffer argued that stupidity is a more dangerous enemy of good than malice because reasoning with a stupid person is ineffective. Stupid people are easily satisfied with their own beliefs and become defensive when presented with contradictory facts.
Bonhoeffer believed that stupidity is not a result of low intelligence, but rather a moral failing. People become stupid by allowing themselves to be influenced by others and giving up their independence.
According to Bonhoeffer, stupidity is a sociological problem that is spread by powerful figures. Power seems to require stupidity in others in order to function.
The only way to overcome stupidity is through liberation, both internal and external. Until someone is free, attempts to convince them are likely to fail.