When you find out about the Belsavis experiments on the Republic side, it's all "That's horrifying" and the senator is like "Don't tell anyone"
When you find out about that on the Imperial side, it's all "Why didn't we think of that first" and "Wow, I didn't think the Republic had it in them" and "Let's take over the program now that it's shut down."
Every bit of corruption and evil in the Republic is matched and far exceeded by the Sith.
Defending the Sith Empire is like glamorizing the Middle Ages. Sure, if you were a Lord it was a sweet setup. As one of the many peasants, it was horrible.
Depends on the npc and they type of character you're playing. Some npcs think it's horrible, some don't. Some player characters think it's horrible, some don't. They did a good job of making it possible to be both ls and ds in both factions, and to be able to find both good and bad things about both sides that make that work. In the movies, everything is black and white, the game has a lot more grey. Why not embrace that instead of trying to argue that it doesn't exist?