Here's another way of evaluating the sanity of religious belief:

It's arguable that the original believers of religion were insane (e.g. shamans with schizotypical personality disorder, temporal lobe epilepsy, etc...), yet with each subsequent believer in your culture, you are less and less insane to believe in it. During past history, it would only take a few insane or gullible people with good oratorical skills getting together to make religion sanely believable.

If you are religious because you see spirits, you are insane. If you are religious because your friend Shaman Bob sees spirits and predicts the rainfall, you aren't very smart, but you aren't insane either. If you are religious because your whole tribe believes in the spirits seen by Shaman Bob and has indoctrinated you from birth, you are not insane at all, you are a typical human.