/generalisations/
1. The conservative mind fears change and uncertainty. The moon for millions of years was merely a vaguely distant astral companion to earth, and harbinger of seasons, moods, and lunacy. For it to suddenly join the concrete scope of humanity's physical attainments was a significant and uncomfortable paradigm shift for some.
2. It WAS a political event. It cost taxpayer money, and it was part of the Cold War space race. So some people were easily inclined to believe either that we
shouldn't have done it, or that we would be highly motivated to pretend to have done if it weren't achievable.
3. Once it was whispered to be a fake -- even in jest -- some people in categories (1) and (2) were primed to accept it, or at least investigate it. And once you're in CT territory, as we know, all "evidence" in support is accepted and all evidence against is dismissed or ignored.
/generalisations/
It's kind of funny -- CTists today bend their efforts toward what they think of as 'scientific method' -- often in pursuit of disproving something in science (climate change, evolution, the moon landing). The contrast is a striking insight into our human brains.
Edit: word choice, punct.