Once upon a time, confident in my knowledge of biology, I was certain that creationists were stupid. But then I read some of their articles and listened to some of their talks, and learned that some of them (not all of them! Some really did prove to be incredibly stupid) were extremely intelligent and well-educated — they were just profoundly wrong, and were using their minds to build elaborate rationalizations to shelter their errors from correction.
And then I discovered that a lot of scientists didn’t understand evolution very well either, and that many atheists were even more ignorant of science than their creationist opponents. So I’ve been learning that some very stupid ideas may be held by intelligent people, and vice versa.
Also once upon a time, content in my privilege of being a person of equanimity with few mental instabilities to trouble me, I was certain that the people who held those bad ideas, if not stupid, were surely insane. How could you believe the earth was 6000 years old or that gods existed or that prayer and UFOs and Bigfoot were real, all crazy ideas without a doubt, if you weren’t crazy yourself? And then, of course, it sunk in that most of the inhabitants of this country believe fervently in a god, so it would require a peculiar definition of insanity to argue that a majority of fully functioning, prospering individuals were all mad. They’ve got some crazy ideas, sure, but that doesn’t mean that the entirety of their behavior can be dismissed as the product of a damaged brain.
And then I met a great many smart, disciplined, hard-working, successful atheists and scientists who admitted to suffering from mental illness…and they were good people! “Crazy” isn’t grounds for rejection of individuals.
Don’t get me wrong: there really are lots of stupid, crazy ideas floating around with dangerous levels of popularity. But you can’t reject them with pat dismissals of their promoters as obviously stupid and disturbed.
So yes, I’ll think twice before concluding that someone with a crazy stupid idea is necessarily mentally ill.