Your belief about atheists is actually a pretty well studied bias, by the way. Here is just one example: https://www.nature.com/articles/s41562-017-0151

And you also say 'God' and 'His rules' as if that is some clear definition or morality. Which god? There are thousands. Which rules? There are many different rules, even amongst the Abrahamic religions alone. Much rape and murder has been committed in the name of god. There are examples explicitly in the Christian Bible saying it is okay to kill people for reasons I and many Atheists would say is wrong. I think you're just biased like most people.

You also say there are some sane atheists, as if sanity is at play. Do you also think most Atheists are insane? I haven't seen any evidence suggesting that Atheisism or religion is an indicator of sanity. Insanity doesn't really accommodate things like morality, religion, or reason. You can't really measure the beliefs of an insane person due to the detachment from reality.