""There are huge swathes of the US who believe that Darwin was a charlatan and that evolution never happened.""
Not just in the US.
I was dating what seemed like a rational, sane man, he was a Nurse, owned his own home, drove etc.
Went to his to have a drink on a Saturday night. He asked me what I'd been doing because I said I couldn't go at the time he suggested.
So I happened to just say that I always watched Doctor Who with my youngest DD.
This prompted a huge rant about how dare it be suggested that he's descended from a lesser creature, that there was a time when people wasn't on the Earth blah, blah, blah and the worse bit, that Dr. Who etc shouldn't be allowed on television. I swiftly left.
I gave him another chance to explain things and it turns out that there are weekly meetings of a whole load of people who share these views. There was enough of them in my home city (Liverpool) to fill a Church Hall every week and they are all 'Professionals' with degrees etc. I was still actively 'recruited' for weeks after we split up, by other members.