Fair enough. But why not handle these exceptions in the rules then? If they don't confer a major competitive advantage then let them compete as the sex they feel like.
But I don't think we can draw this out to a full blown man who identifies as a woman so gets to compete against women. As usual, there is a sensible middle ground, and you have to get into the weeds a bit to sort it out.
Its like people who say only "pure capitalism" or "pure communism" is the best system, when in fact they are both garbage options, and the best is actually capitalism constrained by socialist policies like in Scandinavia. Yes, it's messy and complicated and hard to figure out, but that's pretty much always the case for coming to the best result.
The extremes on either side are almost always wrong.
Anyone who fails the tests for the other cases you list. The governing body of the sport gets to decide, and tests are decided by scientists and doctors.
For the same reason anyone wants to know anything. Because if anyone is to have an informed conversation about this, we need to know how they come to their conclusions. Their lack of transparency is a large part of why this controversy exists in the first place.
Which do you think would be more likely to discourage girls and women from participating in competitive sports, the chance that they might have to compete against a "real" woman or the requirement that they let everyone else know about their private medical records?