The attempt to re-label sociopath "bad people" is one of my chief problems with psychiatric medicine today and I say this as someone whose studied it. It's a program with an agenda and ignores the very real difference between the mentally ill versus those who do criminal actions for gain, social stratification, or ideology.
Labeling the majority of human history's killers, conquerors, slavers, and so on as sociopaths may make good copy but I don't believe it. There's no "evil gene" that can magically be made to go away.
I think of Gul Dukat as a man who voluntarily IGNORED his conscience and the chief source of his torment is the fact that it existed despite his efforts to do so. If he was mentally ill, he wouldn't NEED to. That last little lingering flame of good inside him actually makes him a worse person, IMHO, because he could have listened to it long ago.
Just saying, "oh he was all about being adored and his motivations are 100% pure selfish" undermines him and his role in the story. They were just 90% sociopath and comfortably lies to us by saying that another "normal" person (Cardassian or otherwise) wouldn't do the same in his place.
Human history says otherwise.