In the book, Hermione's race is never mentioned. She's described on as having frizzy, bushy hair, large teeth, and brown eyes. None of these things suggest that she couldn't be a person of color. Furthermore, intelligence isn't a trait that's determined by race, and your suggestion that it is comes across as incredibly offensive and definitely racist. Adding a big disclaimer that you're "not trying to be racist" doesn't fix the fact that it is. Prejudice borne of ignorance is no better than that borne of hatred. By citing Dean's grades, you simplify a diverse cast of people down to a single person's experience. Why not talk about how the first female astrophysicist to graduate from MIT was black? Or the 9 year old boy who can speak 7 languages fluently, and plans to go into international diplomacy? Or the 5 year old girl who has her own math textbook published, one that's being used in COLLEGES nationwide? Furthermore, representation, seeing people who have experienced things similar to you, who you can relate to, is incredibly important. It allows people to see themselves in their favorite characters, promotes the spread of acceptance in children, and lessens the feeling of alienation which springs from not seeing people you can relate to in your media.
This refers to the fact that it is technically the author's choice for what is canon and what is not relating to a book or movie or any other medium of the like. As such, Rowling is justified in using Word of God.
The thing is, people hate WoG in most cases, particularly in regards to Rowling, because of her abuse of it. WoG is fine, and any writer has the right to use it, but when it disregards canon, fans tend to get annoyed.
And, yes it does disregard canon. Hermione is portrayed as white on both the covers of The Prisoner of Azkaban and The Deathly Hallows. Because of how much say the author has in choosing the covers of their books, a book cover can in fact be considered canon, as the author assumedly chose not to express their wishes that the cover be changed.
The movies too are considered by many to be canon, and in fact technically are. As with book covers, as the original author, Rowling could have requested that the role be played by a different actor, presumably a black one, but she did not. Of course, as Warner Bros. Owned the copyrights, it is possible that they disregarded her requests, but that is unlikely.
But in the end, it is the author's choice. Rowling has in the past show a willingness to Word of God any problems away. In fact, I consider much of the Harry Potter series to be Deus Ex Machina the books. However, no matter how much I disagree with Rowling changing the race of a character in her books after the fact, and that is the only part I find disagreeable, it is her right to do so.
In the end, "Monsieur l’abbé, je déteste ce que vous écrivez, mais je donnerais ma vie pour que vous puissiez continuer à écrire."
If this vote is suggesting that Hermione Granger from Harry Potter should be blck, then I completely disagree. For one thing, whites (like Emma Watson actually is) are much smarter than blacks NOT TRYING TO BE RACISTS!!! NO OFFENCE INTENDED AT ALL!!! But is is kind of true, like Dean Thomas. He got a D in potions, where as Hermione got an A.