What singular thing will anger every Harry Potter fan?
Voldemort had a point.
The Ministry of Magic was a joke and was long overdue for a regime change. Hogwarts was a mess, too, with a giant 3-headed dog locked up in an easily accessible room, and a tree on campus that would literally kill you. And don’t get me started on the Headmaster.
The random string of DADA teachers was a disgrace. The only one who wasn’t an active Death Eater or ministry plant (or total buffoon) was an ACTUAL werewolf. Tom Riddle would have been a lot better than Dolores Umbridge.
Why shouldn’t wizards run the Muggle world? Sure, there’s going to be some bloodshed, but that happens in every revolution.