Trans women are women but they aren't female. Gender is a social construct. Sex is not. You can choose to be a woman but that doesn't make you female.
Female atheletes understandably feel that it is unfair to have male atheletes breaking female athletic records. I mean...that's pretty obvious, isn't it?
I'm trying to explain to you why a female athelete who chose to play a female sport to have a more level playing field and to play against other female atheletes might feel that is is unfair to be forced to play against a male athelete and why they might feel that it is unfair to have a male athelete break a female athletics record by such a margin that no female athelete could ever hope fo break it again.
This is not a difficult concept. Gender is a social construct but we're not talking about gender. We're talking about male and female. A male can decide to identify as a woman but she can never be female. A female can decide to identify as a man but he can never be male. You can be equally socially but you will always be different sexually. That's just reality.
You want to live as a woman and be called a woman I'm totally on board with that. You just can't force people to believe that you've magically changed sexes because you haven't.
You can want against all want for it to be different but it isn't and it never will be.
I am not transphobic. Not by the longest of shots and labelling anyone who doesn't buy into the group think as a transphobe completely devalues anything else you might say. I absolutely believe in social equality but trans women and females will never be the same thing.