One of my favorite quotes and observations.
Against stupidity we have no defense. Neither protests nor force can touch it. Reasoning is of no use. Facts that contradict personal prejudices can simply be disbelieved — indeed, the fool can counter by criticizing them, and if they are undeniable, they can just be pushed aside as trivial exceptions. So the fool, as distinct from the scoundrel, is completely self-satisfied. In fact, they can easily become dangerous, as it does not take much to make them aggressive. For that reason, greater caution is called for than with a malicious one. Never again will we try to persuade the stupid person with reasons, for it is senseless and dangerous.
If we want to know how to get the better of stupidity, we must seek to understand its nature…. We note further that people who have isolated themselves from others or who live in solitude manifest this defect less frequently than individuals or groups of people inclined or condemned to sociability. And so it would seem that stupidity is perhaps less a psychological than a sociological problem.
In conversation with him, one virtually feels that one is dealing not at all with a person, but with slogans, catchwords and the like that have taken possession of him. He is under a spell, blinded, misused, and abused in his very being. Having thus become a mindless tool, the stupid person will also be capable of any evil and at the same time incapable of seeing that it is evil.
(Dietrich Bonhoeffer, theologian who opposed Hitler and was executed a few days before the concentration camp was liberated.)