JK Rowling is justified in her disagreement with the tr@ns community

She wrote the books, and created the characters. She has total say so about what sex/gender they are.

She made Dumbledore, the main characters hero and mentor, an old gay guy, which is something that's completely out of pocket for a children's series.

She wrote Tonks as a woman who can alter her appearance, that's it. The LG£T community took that character and insisted she was tr@ns, twisting JKs creation to fit their ideals and refusing to respect what the person who created her decided. Which is extremely ironic coming from the community that insist that someone can be whatever they decide to identify as and it's only their decision that matters.

With all the hate JK got for defending her character and what else came after, it's totally reasonable for her to despise a community that's caused so much grief and tore apart the universe she created that millions of people love.