Calistemon
Chewbacca
Is saying women exist transphobic?
Increasingly, yes it is. And it's "poor sportsmanship" apparently to complain when this person competes in the women's cycling race and wins the world record because they say they're a woman.
Just cheating
That's no woman, that's a misogynistic male.
Some men really hate women succeeding at anything, don't they!
Pathetic.
They do (hate women). And it is (pathetic).
JKR is a great role model for both girls and boys. She showed great perseverance managing to write at all as a skint single parent, and she hasn't forgotten her roots. As others have said, she wrote in a way that appealed to even reluctant readers, so I'm not convinced that she is overrated. These things are subjective anyway.
Her indomitable stance in the face of disgraceful abuse from Trans Activists is admirable. She is able to use her fame and money to stop the more objectionable ones in their tracks, by prosecuting them. Most women who get abuse can't afford to do that, and the risk to their careers of standing up to Trans Activism is too great for the vast majority of women to take. (Google Kathleen Stock if that seems unlikely.)
I have seen and heard countless jibes aimed at JKR, but I have yet to be shown anything that she has said that is transphobic.