A critical psychological need for many autogynephiles is to be included as “one of the women.”
This is also the motivation behind joining women’s sports: they crave “inclusion” and that sense of female community and bonding.
It’s why they get “euphoria” when invited to girl’s night.
But anything that threatens to remind them of their essential dissimilarity with females causes anguish e.g. women bonding over childhood experiences, periods, pregnancy, etc.
This is why “TERFs” are the existential enemy of trans women: it’s a forceful reminder that their acceptance as “one of the girls” is conditional and can be rejected by any woman on of the basis of something they can never change about themselves. It’s like a knife in the gut which is why it leads to so much narcissistic injury and rage.