I wonder if this is some kind of cultural Stockholm Syndrome. The deity from the bible is your worst nightmare: a dictator that has a huge amount of power, dishes out vicious punishments, and can't be removed from the seat of power ever. It punishes you for even thinking of opposing. The followers can't live in total fear, so they convince themselves that living under such a dictator isn't that bad... in fact, it's a good thing... no, the best thing ever. Before deluding others, they've gone to great pains to delude themselves.

It's sad to think many of them will never learn that reality is not like that, that there is no monstrous superpowerful dictator governing them, and that this book they hold as the ineffable truth is in fact contradictory to the overwhelming evidence provided by science and history (and by its own lights poor value as evidence).