I'm pretty sure they didn't write all of the religions of the world. At the core of (almost) all of them, there's a great deal of love and compassion. So much, in fact, that you'd have to understand it at least somewhat to put it there to begin with.
More than likely, all of the religions of the world have been co-opted by the evil (whatever that means) very early on, and have been used to manipulate people ever since.
It would be uncomfortable for the masses to find out that the religions they've staked their entire worldview on were full of shit.
But hey… They're full of shit, lol.