Why is it that religious people insist that atheists are immoral and unethical?

We are but people who claim to be atheist have no grounds of morality. On what is your basis your core. Most atheist comprise their standards off what they feel is good but what about the rapist who feels he is good and what he is doing is good and he is an atheist! GOD says it so it is! Who says what for you, yourself right which you always find a problem. Ask Dexter from the TV show