All threaten the oldest hierarchy of all: man over woman.

Pretty much this. I remember being a teenager and hearing the most basic watered-down gender theory and being really confused and upset. Even back then I knew it was because, for it to be true, it meant a lot of things I take for granted about society were actually totally irrelevant. Unfortunately some people don't ever have to confront their cognitive dissonance, they just use their money and power to enforce the status quo they're used to.

Jk Rowling is a second wave feminist and she’s big mad that people without vaginas can call themselves women and be in women’s spaces.

Unfortunately you could have the best neo-vagina money could buy and terfs would still find an excuse to exclude you. It's not truly about genitalia, it's about being trans.