1. Evil due to insanity. Either his whole command is full of loons, or he is a lone warrior. Who follows the orders of an obvious crazy person?
Evil dude: "Wool socks! Wool socks! Help! Get them off! Ahhh!" *runs around*
Soldier One: "Well, aren't you going to help him?"
Soldier Two: "I was thinking to, but then I noticed he doesn't even have any socks on."
2. He seems rather cold-hearted for no reason to me. Sure, he has to eliminate all of his new relatives, but I don't see how that makes him use and discard people.
3. Evil due to disgust. I can understand this guy's point of view, though it is a little cliché.
I picked number one 'cause he'd be more interesting if absolutely crazy.