I made a similar thread not too long ago about the rise of antiheroes and people rooting for the villains - which I'm sure has a lot to do with aesthetics. While I'm sure it says more about me than anything else that I, quite literally, almost always root for the baddies or, given the situation, antiheroes - Underwood, Dexter, Moriarty, Sidious, Raoul Silva, et cetera.
However, it's not just rooting for them for aesthetic purposes. I literally hold them in higher regard than their opponents; I respect them more. I relate to them more. While this may not be the case with all of those listed, I know that everybody who has seen House of Cards and enjoys it utterly respects Frank Underwood, despite the fact the man is a ruthless, manipulative, power-hungry psychopath.
So, why is this? Do we respect power and pragmatism? Is their something in the ruthlessness of psychopaths, and their sheer detachment, that we find admirable?