Why did this entire thing sidetrack too much into the race stuff?
This topic is about what a woman is, it's actually important to first answer that.
The difference between men and women is so fundamental that ALL cultures agreed that men weren't women and boys weren't girls. In contrast, difference between racial ethnic subsets has far more nuance and variation to it and is not nearly as fundamental to our species as the difference between our male and female species members.
As Sadolite said, and I noticed even when I leaned left for the majority of my life, you cannot have firm feminism and thus female-based women's rights and also female-specific protections and policies, if you're going to never ever define what a woman is. UK's leftist Keir Starmer caved in to this issue and finally agreed to define it biologically after a major bill held in Scotland, I believe, was won early on in his Prime Ministry.
https://www.bbc.com/news/live/cvgq9ejql39t
The clash between hardline feminists and the modern fully-affirmig transgender movement is actually innate and fundamental because the former holds males as a threat to women that have to have policies in place to 'tame' that threat and protect female-only spaces etc. On the other hand, the latter believes a male can become a female and often believes all it takes is him dressing up as a stereotypical woman and saying he is one. This then, according to the latter, enables that male-sex person to enter female-only spaces and count as female on the policies designed to protect them against male 'microaggresions' as well as overt aggression.