people reject the idea of God and Satan. when they do that, they can not understand the concepts of good and evil. everything is relative for them. Marx was one of the most evil influences in history. it is easy for me to accept that he was a Satanist. Hitler is another good example. he, and those he surrounded himself with, were into the Occult. out of their beliefs came great evil. countries like the USSR and China have done their best to remove God from society. they perpetrated great evil on their own people.
however....it is also possible for people to take religious teachings and twist them into evil. plenty of examples of that though out history. you have to wonder what power really influences those people. how much is "human nature"?