[luckylion]

Especially when those alternative explanations are exciting (Spies everywhere!) and simple ("Oh, so that's why!") instead of boring, vague, complex, and nuanced.

I believe there's also a fair bit of package-deals. If you believe in one thing, you trust people more who also believe in that thing ("they see the world as it really is"). If they also believe in something else, that's a strong vote for that other thing.