I've lurked and lurked on threads about this and concluded we need to go right back the start: why do we have women's sports categories in the first place?
To state the obvious, this is because there is a physical difference (height, weight, strength, bulk, speed, stamina) on average between men and women.
Assuming that trans woman athletes accept that this is the reason the two categories exist in the first place, it is surely illogical for anyone to think that it would be fair or appropriate for someone with male physique to compete in the female category.
If they do think that it is fair for a male physique to compete with female physiques, there is then no point in having the sex categories at all and it shouldn't matter to them whether they are competing against males or females.
As they clearly care SO MUCH about being allowed to be in the women's category rather than competing in the men's category, they clearly accept there is a difference (otherwise why would it matter what category they were in?)... and so should logically accept that they, with a male physique are different from the women.
But apparently to call out the cognitive dissonance that must be going on to think there both is and isn't a difference between the male and female physiques is transphobic and must be silenced.