The word "evil" has always carried a sort of supernatural connotation in my opinion. Before I rejected the idea of God, I would go to church on Sunday and listen to the kind, eccentric pastor give his sermon. In everything he preached there was an underlying message about the distinction between good and evil. He never spoke a hateful word about gays or nonbelievers. He always associated evil with theft or murder or cruelty or dishonesty...things that were pretty easy to condemn. Of course the people who lied and cheated and inflicted harm on other are evil, I would say to myself as a listened to the man who I had, and in many ways still have, such admiration for.
Then I threw away faith, however, and the idea of evil became more and more silly. If I was to reject the idea of divinity incarnate, wasn't it also my responsibility to reject the idea of the satanic? I think the notion of an evil force creates just as much of an "us and them" division as does the idea of a divine power picking and choosing habits and people to send a invitation to the promised land.
Of course it's predictable that humans would invent such a label. Who wants to think that Hitler has any similarity to the average, decent human being? Who wants to consider for a second that the spiteful reverend, Fred Phelps, who leads protests against the funerals of soldiers and homosexuals, actually has, in some twisted way, good intentions? Though the label should be expected, however, I don't think it should be tolerated. Instead making a futile attempt to label these people as supernaturally subhuman (and I know it's tempting) It may be more beneficial to look at the human motivations (the thirst for power, the tendency to fall into senseless, dogmatic habits) that spark such horrifying behavior.