And what if you decided to exclude Dutch people because statistically they are taller than average?
What forms of discrimination are we allowed to engage in?
For the most part, western societies have decided that we should not discriminate on the basis of factors which are superficial, but we can discriminate on the basis of factors which are substantive. Race, for example, is mostly considered superficial for employment (actors playing roles of historic persons is an example of a rare exception). Eyesight is considered substantive for many jobs (you can't fly a plane if you're blind).
Is the difference between men and women substantive? When it comes to sports, I think the answer is yes, and society for the most part agrees, which justifies segregated mens and womens sports. Is the difference between trans women and women substantive when it comes to sports? I think the answer is still yes.
You have appealed to the existence of other differences, such as height, which can also be substantive for sports, and questioned why we don't segregate on that basis. Well, the answer to that is that the existence of a substantive difference doesn't always
require you to segregate on that basis. In the case of sports, it's basically a question of what basis people
want to segregate along. It appears people aren't interested in a separate basketball league for short people. They are interested in a separate basketball league for women.
So do fans
want trans women competing in the womens sports leagues? I think the answer is largely no.
And I don't think any further justification is actually required.