No one here bemoans the existence of trans people. If you want to discuss, it’s a basic requisite that you actually do so honestly, based on what we say.
People have the right to be and present as they wish, and feminists are against sex based stereotypes so support gender non-confirming presentation.
We don’t segregate in our society except in specific circumstances for specific reasons. We understand, for example, that people from specific ethnic communities may want services and groups targeted exclusively at them, and these are funded accordingly from public money.
We have sex segregated services where women are at risk of sexual voyeurism, intimidation, or assault, or survivors may be traumatized by a male presence, or where, as in sports, women are unfairly disadvantaged ( it’s sex that effects performance, not internal gender identity).
Unless you can show, as a minimum, that men who identify as women present the same risk as women, and that no male predator or voyeur will use this loophole, and that make bodies have no physical advantage over females, then the case for this sex based safeguarding and sports remains in tact.