Not so sure it's stupidity, it could also be malevolence but I would bet on wilful ignorance. Wilful ignorance is like faith, no matter the evidence to the contrary the ignorance will still prevail even if it forces you to disregard your own senses and indeed reality itself.
Michael, I have spent a lot of time reflecting on what makes people tick, particularly regarding what motivates them to behave as they do, and while I don't doubt it may sound conceited of me to say so, I am way past thinking in the terms you use. In the first place I have a very different , I would say, far more sophisticated sense of what evil really is than, as is what I see as the usual, that people have evil in them they act out. What I mean by this is that I think people assume evil to be real and a force in human nature or even a force that exists in the universe itself in the form of some corrupting malevolent being. Particularly that latter invention, the devil, etc., is a bunch of horse shit to me.
Similarly with willful ignorance. I don't have a problem with the words but I can't stop with that. I want to know why such willfulness exists. Just saying it is there is meaningless to me. So all of the attributes you may want to ascribe to it, while they may be perfectly accurate, only describe the symptoms and not the cause.
Why do people appear to be malevolent or willfully ignorant, Michael, what makes them that way? And in particular, and this is very very important in my opinion, are they to blame for how they are? Could they or should they be different. Why do they not change for the better and could anything make them or help the to change? If we cannot answer the question as to why people differ in their capacity to do good or listen to reason, how will we properly evaluate the human condition.
Like Einsteins incomprehensible insight into the nature of time and space, matter and energy, there is a very simple, in this case equation that throws light on the matter, of course in my opinion.
The answer, I believe is that the reason that people act as we speak about here is that their ignorance is a matter of life and death, that we are psychically dead and do not want to know it. And the reason we are dead is because, once long ago we were told a lie too difficult to live with, that we are worthless as human beings, each worse than everyone else. And the only way to know this is true is to feel it, in other world to relive one's psychic death all over again. Naturally, there are also a million ways those of us with some integrity left, who survive in denial with a breathing tube, find to avoid confrontation with those deeply repressed feelings. The thing that saves, I guess you could say, is that our deepest nature, not what we feel but our true potential, is to be gods, so to speak. We become instead professional egotists, but not knowing the substitute nature of that form of self delusion, we have to constantly be on guard to protect of substitute integrity. Willfully ignorant them might just as well be called willfully conceited.
Unfortunately, while that is easy to see in others, we don't see it in ourselves, generally speaking.
And because we had to become as we are to survive pain no child can consciously bear, no sin can be attributed beyond this original sin. We denied that God is within and all the rest follows out of that.