I understand people having concerns about unfair advantage when it comes to people who are competing at a very elite level where small advantages can make a big difference. In that case, it makes sense to me that an organization might want to do some research to compare the athletic performance of transgender women who have transitioned (taking hormones, etc) with the athletic performance of highly athletic women in their weight class. If they find that there's a significant advantage, just because of them having had gone through male puberty, then maybe the organization will set a handicap or something.
But elite competition is a separate issue from just taking a class and practicing together. In the latter case, I really wouldn't see what the big deal is with that. They're just trying to learn, same as you.