The cultural left is against her for being very visibly transphobic (along other things). Additionally religious reactionaries historically don't like the fact her books are inspired by historical witchcraft practices, as pointed out in the meme.

To quote wikipedia's summery:

...Whited asserted in 2024 that Rowling's sometimes "flippant" and "simplistic understanding of gender identity" had permanently changed her "relationship not only with fans, readers, and scholars ... but also with her works themselves".

https://en.wikipedia.org/wiki/Political_views_of_J._K._Rowling#Transgender_issues