Thanks for asking. Your post unlike others’ at least demonstrates an understanding of this premise I’ve banged over and over: “You should either be able to identify performance advantageous traits for inclusion/exclusion OR accept that you also just have a definition that doesn’t necessarily confer any performance advantage or disadvantage.”
Let me explain the position. I believe most of us agree on the following premises (except the NitpickingVerboseLady who might get stuck on some inconsequential detail and type two pages condescendingly educating me on basic biology or general knowledge):
1) We have at least two groups amongst humans who have distinctly different abilities, so we need at least two categories for the sake of something called “fairness” we care about a lot.
2) What is fairness? If one person can never be remotely competitive (about 8-12% or more weaker) with another no matter how much they train, we intuitively think it’s unfair for them to compete with each other.
3) “Performance” alone can not be a determiner of to which category one belongs, otherwise one would just run slow in trials to compete in the weaker category, so we look for an innate relatively unchangeable feature that is performance-predictive, ie people who have that feature are overwhelmingly likely to be in the weaker category and people who don’t in the stronger category. To answer your specific question, being slow enough is not enough for the 462nd ranked male athlete to be included in the weaker category.
4) Many people for the longest time and to this day believe that that feature is being born with ovaries. That is not an unreasonable position, but it should be recognized that it is being used as a performance-predictive feature.
5) Nobody thinks ovaries are like lead weight that make you slower in and of by themselves, rather ovaried people go through puberty without testosterone-charged physiological developments that result in distinctly weaker features than the stronger category (of testied boys).
6) There are other performance-predictive features like the several physiological features you listed. Endogenous fT is widely thought to have an important performance-predictive effect in various sports. It’s far from perfect in any sport. There are others like lean mass, VO2Max, height, leg length, or whatever is most performance-predictive for that sport, “sport-specific” as you said.
If your argument, for example, is ovaries are the single-best predictor of weaker performance because they result in (say) narrower shoulders on average, and wide shoulders are important for performance in sport X, then how is it fair to include a cis woman with shoulders wider than a trans woman but exclude the trans? What does fairness even mean then? If the extent of diversity of physiological attributes within elite cis women extends to be superior to that of some elite cis men (as studies like those by Sonksen et al 2018 show), how can you define “fairness” without drawing a line somewhere?
Hence the claim that you better either use current performance-predictive physiological features to include/exclude any person in the weaker category OR accept that whatever other criteria (like natally ovarian) is not necessarily predictive of *dramatically* weaker performance than a trans woman.
The above is an extreme position but the only one that is consistent with non-binary gender and intersex cases. The world’s governing bodies are never going to go back to a binary model or a position that denies a trans woman her identity (although people on LR may call her delusional all they want), so it’s either a separate third category for trans and intersex OR inclusion/exclusion based on performance-predictive features beyond just natal ovarianness.