Why has J. K. Rowling never acknowledged that casting a black actress as Hermione in Harry Potter and the Cursed Child was a retcon of the character from the books?
Unless she actually comes out and gives a statement on it, we
really don't know. When asked about it, she defended the change by
stating on Twitter "brown eyes, frizzy hair and very clever. White
skin was never specified. Rowling loves black Hermione". Of course
she also has acknowledged on several occasions that sometimes her
stories had inconsistencies that she didn't notice until others
brought them up. In this case she overlooked the fact that Hermione
is repeated stated to have bushy BROWN hair. All of the black
actresses playing Hermione in the play have had very much BLACK
hair. All the official illustrations of Hermione in the original
books certainly do not have her portrayed as black. J. K. Rowling
has often mentioned that she saw herself in Hermione when she wrote
her - and J. K. is not black. So yes - it is a retcon.
When it comes down to it, it doesn't really matter all that
much:
1) Hermione is a fictional character so all "facts" about her
are made up anyway
2) Bushy hair is actually a common trait among many women of
black African ancestry if they let their hair grow longer and the
bushiness of Hermione's hair is generally made more prominent
mention of than the fact that it was brown.
3) Getting a good actress in the part was far more important
than sticking to the book 100%. One would assume that Noma
Dumenzweni was chosen based on her strong acting - she already had
an Olivier award for her role in Raisin in the Sun. Once she was in
the role it made sense to follow up with another black actress when
they needed someone to take over her role.
4) Hermione's skin color is not the only inconsistency - in both
the play and even in the movies. It is repeated mentioned in the
books that Harry has BLACK hair and GREEN eyes and the actor
playing him in the play has BROWN hair and BROWN eyes. Using Daniel
Radcliff as Harry in the movies is also a retcon when you realize
his eyes are not even vaguely green despite it being such a big
deal in the books about him having emerald green eyes like his
mother - or as put by Ginny
"His eyes are as green as a fresh pickled toad,
His hair is as dark as a blackboard.
I wish he was mine, he's really divine,
The hero who conquered the Dark Lord."
- Harry Potter and the Chamber of Secrets.
Harry was also supposed grow up to be rather tall like his dad
and Daniel isn't.
Perhaps J. K. Rowling hasn't acknowledged that changing Hermione
to black is a retcon because she doesn't consider it to be
significant. Compared to the other inconsistencies in translating
the books to other media like movies and the play, it really is
ultimately rather insignificant. It probably sticks out to a lot of
people because they got the image in their head of what Hermione
looks like based on the books and it clashes with their established
"head cannon".