I have thought of the author's argument myself several times over the years. Maybe Brown vs Board Of Education could be a precedent here!!
What I do not get about the case itself is why a grandfather of a Boy had any standing in this matter. Did he want the grandson to have a better chance at punching the lights out of a Trans* classmate?? I guess that it was a poor shot at getting the girl to have to "man-up" or gramps was afraid that his grandson would want to wear a dress too. I have too many bad possibilities in mind here.