I see where you are coming from Vampire.
However, many feminists are not actually 'Trans Exclusionary'. Female people of all genders are included in feminism. Even if they reject it because they don't want to admit they are female. Feminism isn't for 'women'. It is for all female people of all ages. Therefore, what feminists campaign for is to collectively improve the lives of all female people in the face of needs arising from oppression and discrimination caused by patriarchal principles and actions.
Male people who declare that they are women are generally part of that.
Every single male person who takes the place that has been set aside to encourage a female to achieve their full potential, be it sport, art, writing, STEM is continuing that cycle of discrimination. And every single male person over about 8 years old who enters a space set aside for the needs (safety, dignity and privacy) of all female people is harming those female people by removing the space they need. Their entry immediately and automatically makes it a mixed sex space.
Because no person can change their sex even if they have surgery and have cross sex hormones.
And this is not transphobic to state. Despite that there will be those on this thread who would like to frame it as such.
But no. Feminists are not 'trans exclusionary'. They are 'male exclusionary'. Just as they always have been.