honestly, all this effort should be made to find ways to allow them to complete, not just outright ban them. Require them to take testosterone reducing therapies until their levels are below a certain range. Do something rather than just outright ban them. That is the most extreme solution, why not try something better.
Every time you are saying, "You can't do this because you are different" you make it easy for people to equate "different" with "wrong". You are separating them from everybody else. These are kids who are just looking for acceptance. Next it is the bathroom issue. Finally you are saying to these kids that "You can't do all those things that other kids can do, but 'go be who you want to be'".
Do people really think that kids are out there trying to game the system? That how they would do better in sports is a considering factor in the decision to live their life as a completely different gender?