"It's possible to establish ancestry via genetic analysis. Doing so by visual appearance however is racist pseudoscience"
No it’s not racist! It’s a perfectly reasonable assumption based on centuries of human history. It might be WRONG, but wrong does not equal racist. If you were to look at me and assume I was of East African heritage and then discover later that I was West African and Caribbean, that doesn’t make you racist, it’s just a mistake.
Why is the word "racist" so light and meaningless to people lately, that it can be thrown about at the slightest thing?! Racism is a real problem with real life consequences, and seeing the issue treated so frivolously is really frustrating.
White and black (and Asian for that matter) are categories. Broad ones at that, but they're reliable indicators, along with others like eye shape, hair colour, etc., of race (or ancestry or whatever word you'd like to use). Are they perfect? No. Do they need to be absolutely perfect to prevent us from throwing out the entire concept of objective biological reality?
"A person is a woman, if they are a woman. It is that simple. But also not."
And here it is. This is the double-think that I've been trying to point out in your argument this entire time. Do you not see why this statement comes across as nonsensical? Maybe this isn't exactly what you meant to say, in which case please elaborate, but as it stands, nobody with a fully functioning brain could accept this.