Every small town in Red State America has one blue-haired Karen with a "In this house we believe..." sign in her yard.
She moved there from Portland.
She has nothing but time on her hands. She gets involved in everything from the school board to the local library. She runs for city council and wins with a dozen votes because nobody shows up. While her neighbors enjoy football games and quiet weekend BBQs, she's busy being an activist.
It would be as simple as having all the biological females refuse to participate in any event allowing biological men to compete against girls. They might be able to ban the first five girls for doing it, but they can’t ban all of them.