Hmmm ....
Joseph Stalin: atheist
Mao Tse Tung: atheist
Pol Pot: atheist
Adolf Hitler: irreligious
Seems to me a whole lot of bad people do a lot of of bad things and use whatever they want as a cover. As bad as religious wars have been historically, wars and atrocities by atheists or agnostics or NON-religious reasons have been 2 orders of magnitudes worse.