The problem is that someone who's transitioned is no longer a man. After undergoing surgery and hormone treatment for a long period of time, a trans athlete falls somewhere between men and women in terms of capability. They'd have no more success competing against men than naturally born women would, yet they still have advantages when competing against naturally born women.
Unfortunately, while the most equitable solution might be to create a separate category unique to trans individuals, there aren't enough trans athletes to make it feasible (yet?). It's rather sad that transitioning means a person can no longer compete in sports, but I'm not sure there's a better alternative.
It's your decision to take drugs that destroy your bodies ability to compete. It's the same as people who decide to eat way too much and similarly destroy their bodies ability to compete. They don't need to make new 'fat person's divisions for people who eat too much. If you want to compete in sports at a high level taking female hormones is detrimental to that.
Is there actually an advantage? that's toted. but no one can ever point to real data about it... and all the data suggests the exact opposite... that for most cases: cis-women out-compete trans-women.
>The problem is that someone who's transitioned is no longer a man.
Sticking feathers up your butt does not make you a chicken.
You still have your larger bone structure. Larger musculature structure and different muscle insertions. different ligament structure. different skin structure. different grip strength. Broader shoulders, narrower pelvis, different angled limbs. all of that isn't going away even if it atrophies. And you aren't going to let it atrophy because you are an athlete in training managing your dietary macros. Maybe recovery isn't as efficient lacking so much excess testosterone but you still have some.