I agree the fact that it's very hotly debated in the US is part of what makes the US such an infamous example of this irrationality, but I would say the fact that the US is a scientifically advanced first world country definitely also contributes to why this is a phenomenon to so many people. Third world countries don't exactly have the best education system. The US (even though it gets a lot of slack) still has a comparably very good one, that should reach beyond "god put us on the earth with magic, the end".

And it does reach beyond that, the whole "teach the controversy" is an eccentricism of an otherwise science-based curriculum.