RE: CAIS are men, not women, and prove sex is binary
A female is not: "identifying" as female, growing up as female, socializing as female, dressing up as female, and "passing as" female.
A woman, a female, is an organism that can bear offspring and/or produce eggs under the right conditions.
CAIS are males with an inability to respond to androgens. The product of the inability is a male with a pseudo-female like appearance, creating the illusion of a female.
Beneath the layers, CAIS have no internal female sex organs - no uterus and no ovaries. They have testes - the male gonads that produce sperm. Their bodies were supposed to support the production of sperm and failed. They are men in every sense of the word.
The only reason they even know they are intersexed is because of modern medicine
The reason humans know they are humans and not another specie is modern medicine, and study of genes. Surely you wouldn't claim humans were not humans before they learned of what separates each specie.
CAIS were not women before modern medicine. They were disordered men.