Even my grandmother wouldn't personally admit she thought space=heaven (my mother thinks she did, however), but she definitely didn't have the concept of the moon being a world in orbit about the earth. It clearly wasn't real to her, hence it wasn't possible for people to go there.

The question at the beginning of the thread was how the hoax started - for some at least, it was that they simply couldn't accept that people could go to a light in the sky. To some, it was impossible, or at least made no sense in their world view.

(Incidentally, going back to the top of the thread, John W Campbell was known for writing very provocative editorials, and wasn't above lying through his teeth just to get a rise out the magazine's readers. He may really have believed it was a hoax, but I wouldn't be surprised if he knew it was real. He had even written a story himself about a flight to the moon and easily understood the astronomical details.)