What did Shannon say about the book that wasn't true? Notice she does not say that the character in question is a main character or--ultimately--the perpetrator. Just that the character exists. Since Rowling herself states this character is based on the two real-life perpetrators from 50+ years ago, I'm not sure what you are alleging is misrepresented. Or maybe you just think it's ok to have a character coded in that way, especially when the author has already stated how much she dislikes (and misunderstands) trans people.