>most things are made just to be good, at least at the start.
That doesn't necessarily contradict what I've said. BUT: Almost everyone is brought up thinking that this egalitarian stuff IS something good. This idea of freeing ever more oppressed people is everywhere. You learn about history this way even. 
So the authors put things that even we agree are good values, but also have themes that are just a tiny bit *more* egalitarian than mass opinion. Nobody will actually give them pushback, except for fringe people, but that's the point. They put it in because they expect people to praise them for it. Because it is a virtue to be egalitarian!

Harry potter also has other things Rowling expected praise for, and some motifs are going to have their "stalin erases the guy from the picture" moment. One day they will remake harry potter, and you bet your ass they won't again portray the magic government as impotent, fearful and oppressive fools that try to hide the truth about the world.