This comment by U.S. editor, Arthur Levine, is the best summation as to why Rowling is incorrect in her thinking.
“I know you and I know you aren’t speaking out of hate, but I do have a different point of view about this. Gender can be ‘real’ without being established irrevocably at birth by one’s chromosomes or one’s genitals. The brain is also an organ that determines gender. Once someone transitions to make their physical body reflect their gender identity, then the ‘sex’ they then express is real. Trans women ARE real women, in their minds and in their bodies. Medical intervention on one person does not invalidate any who don’t need it.”
For those that are calling to boycott (again) the Harry Potter universe in all its forms — from book burning to refusing to attend theme parks — I get it, but it’s harming the wrong people. J.K. got her money. She’s richer than God.
Think of the Harry Potter universe as a child of a parent, in this case, J.K. Rowling. That child has grown up and is a fully realized individual separate from its parent despite any role the parent still actively plays in its life.
Burning the books is foolish because they’ve already got your money. You’re only hurting the planet. Not attending theme parks or movies or buying merch is hurting the hundreds of thousands of people who work to make this universe live its fully realized life. Actors, directors, designers, production, editors, writers, manufacturers, etc. The list goes on and on.
I understand being upset by J.K. Rowling’s thoughts on trans people. Donate to an organization that supports trans rights and trans issues. Share a story of someone you know who’s trans. Work to make this a better world. Write a letter to J.K. Rowling to express your viewpoint (respectfully).