"There is a point when rationality is non-adaptive, so to say someone doesn't have a reason for being irrational is short sighted and taking the very complex human being for face value."
I said this in another thread and it wasn't understood. Since it's an evolutionary psychology topic, it will be more productive to discuss it here than the religion section.
Let me first clarify that the above statement does not imply "rationality is non-adaptive"
Rationality is guided by reason and is thus predictable by those who know reason.
So it can be useful to seem insane to people who may try to manipulate you.
This attitude, to hide one's true intentions is very selective. For example, in general if you want a mate you don't walk up to a prospective gene pool and demand their participation in your gene's evolution. Much about social interaction is deceptive in nature, although not in the sense that we are consciously aware of it.
Religion and more precisely, the idea of God, may be an expression of insanity, hiding one's rationality from the world.
Just because someone gives a few "bad" reasons for believing in God, doesn't mean that those are their reasons. Maybe they are just "bad" at justifying their actions. Maybe they are hiding their real reasons as an adaption to remaining unpredictable.