Nobody believes utter lies. For a lie to be believed it must be bundled with some truth.
Evil is believed and abided to because even an evil man is not truly evil deep inside. He feels the being evil matches with his evil environment. And although one might be determined to do the worst to another, that another might discard that possibility as untrue and have faith in his good intentions –he will never be completely certain though.
God –how many civilizations that had never contacted each other have believed in God, and how come? Some atheists assert it was because they feared death. Well, I would fear the possibility of eternal suffering much more than the possibility it would all end if I died. That’s not it. Others say those older guys were dumb apes and now we have evolved; ‘we’ nearly destroyed the whole planet a few years ago, and now we’re about to ban love, sexual relationships and procreation. In what ways have we evolved, towards self-annihilation?
Everything everyone believes contains a portion of truth. If we could have some theoritical truth and we injected some lies within it, we would have a potentially dangerous outcome. And then another from an opposing side could point out that the whole bundle (the truth included) is all wrong, and whomever says otherwise is stupid or something. That’s what happens when one generalizes with left vs right wing, theism vs atheism and so on. They deny the whole thing they oppose including the truth. That’s how dangerous generalities are. One could say ‘people’ this and that, and another couldn’t argue. But who would he be talking about –‘people’ whom? Who knows billions of men and women?