Well, I'll admit that I hadn't even really thought of the option where they know it's evil but they just enjoy it until these responses. I figured they'd either hate their job or have convinced themselves that they're actually doing good. To be fair I think a lot of outwardly-evil people have convinced themselves internally that they're good people.

The question isn't whether there are bad people who enjoy what they do but whether they recognize that what they are doing is bad rather than deluding themselves in some way.