There's a difference between a cisgendered female and a transgender female, but not a major one in this context.
I think the problem there is privacy laws. That someone is undergoing GAC would be covered by HIPAA and not something the other school should disclose.
I have to ask, how did she NOT know this other kid was transgender? I'm assuming she hasn't had top or bottom surgery. I doubt she was even getting hormone shots.
Now, before Trump started unconstitutionally mucking with things, the NCAA had a good rule for transgender athletes. You have to take one year off from competing to undergo GAC.
This won't be good enough for people like Riley "Wah, I didn't get my fifth place trophy" Gaines, but it seems fair to reasonable people.
Well, it kind of is.
If this were a boy pretending to be a girl so he could get his rocks off feeling up other girls, that would be unacceptable.
If there were a case of two girls wrestling, and a hand went somewhere it shouldn't go by accident, that is unfortunate, maybe the ref should have caught it and called a foul.
The acclaim of transphobic bigots everywhere?
Again, the problem her is the ref didn't see it, it's not obvious from the video, and none of the spectators saw it.