Tbf the whole idea of 'separating the art from the artist' is not a new or a radical one. Roland Barthes literally wrote his 'The Death Of The Author' essay on exactly this kind of theory back in 1967: that once a work is published, it no longer is no longer bound to the author and their intentions but instead it becomes its own entity that belongs to the reader and their interpretation.
Not everyone agrees with Barthes but Carrie isn't wrong here. JK Rowling created Harry Potter, yes - but its success isn't down to her words alone. Not just because of the films but because of every kid (and adult) who read it and imagined their own Hogwarts. I mean, just looking at the sheer volume of Harry Potter fanfiction has existed since the early noughties, you can argue that Harry Potter hasn't truly belonged to JK Rowling for
years.
(As someone whose degree involved Fan Culture Studies, including my dissertation, this is kinda my jam. Just... never underestimate the power, knowledge or intensity of fan communities
Even just look at Tattle or GG - we're technically an anti-fan community but a community nonetheless who interpret/analyse what Carrie produces very differently to what she intends. But that doesn't invalid how we feel just because it's not the preferred reading
)