because it denies women’s hard-won sex-based rights.
It does not do that in any way what so ever. It is a dog whistle, the mask she hides behind to spew her bigotry, and you have either fallen for it or are using the same tactics.
A sex-based definition clarifies the “people who menstruate” conversation
No, it doesn't, because of the reasons I said above:
A study about menstruation and its effects on the body is in fact irrelevant to the very young and the very old. “Should we have supplies on hand for people who menstruate” means the very young and very old are not relevant to the discussion.
As I said before: The obsession with not allowing the term "People who menstruate" actively harms cis gendered women who do not menstruate, because it says "You are not a real woman." Once again, a bigot has "defended" 'traditional' gender roles so hard they have looped around to harming cis gendered people in their attacks on trans people.