do religious people really believe?

[Nobody]

I think those who claim to believe do so largely because they're afraid not to.

Project much? Maybe you don't want to believe because you're afraid of how that might have to change your life to accommodate religious convictions.

If I wanted to set aside the intellect, assume a posture of self-deprecation, and worship a malevolent psychopathic imaginary friend who's credited by mens writings to have committed global genocide by drowning the whole world because he didn't approve humans behaved like low life humans after he created them that way, after he created his own adversary whom he consorts with to tempt those same humans toward his damnable judgment, you might be right.

Then again, you're not.
So there you go.