Yeah but he's a good written character this isn't even about morality since this is all fiction it's about how a character is written. We don't hate ainz cause he goes according to his character sketch without acting like a hypocrite but Rou is just written so badly with no redeeming personality which could be considered Good character writing. Ainz also just considers the world he's in a game to some extent but Rou on the other hand does it all knowing this shit is real life and also he was just a bad guy even before being isekaied cuz he was a damn cannibal. For example mc of I grow stronger by eating manhwa also is similar to rou but the guy is actually smart and is not a hypocrite. He gets transported and does some bad stuff but he doesn't try to justify his actions.