I thought this contradicted at least some of what JKR said about the later (post-Hogwarts) reformation of the wizarding world accomplished by Hermione Granger, but it seems JKR just mentioned laws favoring pure-bloods, not laws favoring an aristocracy/nobility. The relevant passage is this:
After the final battle at Hogwarts, Hermione Granger attained a high position in the Ministry of Magic, first through the Department for the Regulation and Control of Magical Creatures. There, she continued her work with SPEW, working for the rights of underprivileged non-humans such as house-elves.
She then went on to attain a high position in the Department of Magical Law Enforcement, eradicating the old laws biased in favour of pure-bloods. Along with Harry and Ron, she helped to revolutionize the Ministry and reform the wizarding world. At some point, Hermione, Harry and Ron were all featured on Chocolate Frog Cards for their accomplishments.
I thought this contradicted at least some of what JKR said about the later (post-Hogwarts) reformation of the wizarding world accomplished by Hermione Granger, but it seems JKR just mentioned laws favoring pure-bloods, not laws favoring an aristocracy/nobility. The relevant passage is this: