Erickson explained that growing up in the Sith Empire, a person would know there is an Emperor and that he saved their people's very existence. They would also know there is a much larger society out there who, "deemed your people and your religion not worthy to exist." In fact, Erickson even went so far as to say, "[The Sith] get chased out of the galaxy. In fact, in the lore, chased to the point where the Jedi believe they are dead. This is very close to genocide! The Jedi believe these people to be unredeemable."
It's very interesting explanation of a culture and people that could've otherwise been portrayed as mustache-twirling villains. Obviously, this is only a taste of the lore waiting for us all once Star Wars: The Old Republic launches but it's quite the preview if you ask us.