Can someone explain this to me?

Why do people hate the Emperor so damn much? I’ll admit been a bit since I beat the game for the first time, maybe my memory is fuzzy but I still can’t really wrap my head around what was wrong with the guy. He kept Orpheus chained up and I’ll admit that wasn’t great, but other than that and the whole hiding his identity thing I really didn’t notice anything else that stuck out enough to make me hate him. I’m assuming I probably missed some dialogue that makes him stick out as awful.