I am not understanding why this series seems to be so controversial and the Nazi show is not.
There are a LOT of people who, rightly or wrongly, consider the south/confederates to have been the good guys, and are no doubt worried that that they will be portrayed negatively. Virtually nobody thinks the Nazis were good, so there’s nobody around to worry about them being portrayed in a negative light.
I don’t think the people that are complaining believe that the Confederacy were the good guys. I think they believe just the opposite.