Caster Semenya is a cis woman, not trans. People are so preoccupied with stripping the rights of trans people that they ended up stripping away the rights of cis people while they were at it.
It's funny how this gets spun as "discrimination against women" when it's more "discrimination between women". Only women athletes want Caster excluded. No men athletes find Caster threatening.
Caster's case has nothing to do with trans people, it's more that she has rare biology (intersex) but happened to be raised as a woman.
Since her rare biology gives her some of the same advantages as men (elevated testosterone) the question is whether it's more fair for her to compete with men or with women.
She can easily beat many women, so some women feel it's unfair for her to compete with them.
