Keeping them out of female sports, I agree with, it’s unfair and unsafe. This, however, doesn’t pose either of those risks so I don’t see the big deal.
Obviously if they were to enter in any sort of competition he would have to sit it out, but I don’t see this any different than males that perform on female teams, usually the men catching females dropping from high distances, something only a man(or a very strong woman )would be able to perform safely.
Is this creepy, sure, no denying that. But if he doesn’t pose a risk to other female athletes, I see nothing wrong with it.
It’s not like he’s showering in the same locker room. Obviously that would be an issue if he were.