It means not believing in a book that was created over 2,000 years ago by men who may or may not have a psychological disorder. Let me break it down to you like this. If I were to go up to you and say that “god” told me that it’s okay to murder thousands if not millions of non-believers, would you consider me to be sane? If I told you that the other day I saw a burning bush and it spoke to me; would you consider me to be sane? Would you direct me to the nearest mental institution? I’m guessing your answer would be yes. But 2,000 years ago when psychological disorders weren’t understood, these things were absolutely normal. Why would you question someone’s belief in “god”; lest you were a non-believer (and therefore cast out of society).
I have a few religious friends who have actually prayed that I’d someday realize that I was wrong all along and would finally convert to Christianity or any of the other bogus religions out there. I don’t see why I should be prayed for. I’m quite content being an atheist. I’m quite content going to bed at night not praying to a make-believe “god”.
My final thought is this… I’m not going to lay awake at night, wondering if after I die.. would I regret being an atheist. I’m not and I won’t. Ever.