Gender identity doesn't affect anyone except those who believe in it.
Changing society and the law based on gender identity affects every single one of us.
It condones the sexist belief that men and women's minds are just different as a fundamental state not a result of living in a sexist society.
It imposes on every single woman (or man) a redefinition of her- or his- self as someone with a certain type of mind rather than someone with a certain type of body.
It destroys the protections and opportunities created to support female people dealing with living in a sexist and
sometimes outright misogynist society.
It invalidates women speaking about and politicising their experience of being female.
It encourages people to believe they need to adjust their body to match a feeling in their head and then gives them harmful medical treatments in an impossible attempt to do so.
It allows dangerous men access to places women are vulnerable.
It allows sexist and arrogant men to not just speak over women, but to take our place and speak as us.
It requires women who do not see themselves as people of wommamy mind but simply as people of female body to accept intimate care and sharing vulnerable spaces with male people even though they have neither body nor gender in common simply because the man's assertion that he is like her is given credence over her assertion that he is not.
Oh hang on though, there is someone who isn't affected. Male heirs to primogenic estates or titles don't lose out because they specifically remain the real male heir regardless of whether they or their siblings change gender. So that's nice for them.