As many view sex and gender as completely different, they feel that the word 'woman' is only related to gender and 'female' to sex. I've seen/heard this argument umpteen times, even by those who consider themselves neutral in the debate.
There's a really bleeding obvious problem here though, female what?
A female goat?
The word for a female human is woman. We are accused of being dehumanising when we called TW men but at least 'men' implies humanity. Referring to a group of biological women as 'females' is the kind of language woman-hating incels use to dehumanise us.