Visual impairment presents an interesting parallel.
Far more than sex, visual impairment is a spectrum. Some people are absolutely and entirely blind, some see very well, and in between there are people at nearly every imaginable shade of ability in the spectrum.
Since this is how sex is supposed to be according to gender theorists, this should present a salient avenue for comparison and analogy.
The Paralympics event for the visually impaired is for people with very significant visual impairment. Now, it could well be that for many sports, just being visually impaired enough to need glasses (and maybe having funny-shaped eyeballs that don't take well to contacts) would be a significant impediment to elite achievement. Yet for those people who are in the middle (who exist in numbers significantly higher than those with severe impairments who might be Paralympic-eligible), it's kind of "tough luck." The Paralympics aren't pressured to admit every person who is even mildly visually impaired. They're kept for the people who are most-impacted by their difference.
No one gives them a hard time for it. No one would even say that the blind athletes should make room for and pity the sighted but visually impaired athletes who may not be able to successfully compete in elite athletics because of their sight but aren't disabled enough to be in the Paralympics. CERTAINLY no one would say that it was fine for a sighted person to compete, as long as they documented how they'd kept blinders on for a year (at least whenever they had to come in for testing!).
This analogy shows how ridiculous it is for us to even be considering intersex people/people with DSD competing in women's leagues, much less trans people whose biological sex is not in doubt as male. Even a blind man could see it.