Quoting admiralWillyWilber,
First I would like to see civics instead of governments.
Just to be clear, Civics means the study of the rights and duties of citizenship. This has very little at all on how one conducts government. So it would be good for a research title in the research tree, but not very good at describing what type of government is being used.
As to the fact that Dregnin can be democratic, I can fully see this in the terms we have today. No corruption, just the policies that come from this government may not be what we like to see happen. If you are evil doesn't mean you crave power, they could have disdain of being in charge or have power. Also, some evil happens because of boredom,
"Why did you enslave the Thorians?":
Option 1: "They were there... and I had nothing better to do."
Option 2: "Because I wanted more time to play Dregnin Civ 3 and needed people to do the work for us..."
Option 3: "Isn't that what it means to be a Thorian?"
Option 4: "Do you know how hard it is to work in that heat... I didn't want to do it and the Thorians don't mind it so much. They told me that they would rather work in the field than be shot... So we let them do what they want to do. Who am I to deny them the chance of a lifetime."