In posts like this and elsewhere, commenters kept claiming the noun female to refer to a human is generally derogatory or offensive.

Someone wrote

Occasionally my partner does or says some things that remind me of the “manosphere” aka 4chan neckbeards.

A perfect example was that he sometimes says “females” when he means “women”. I explain that it’s not a swear word but it’s still derogatory. I explain why. Once I did, he understood and stopped doing it.

Despite abundant evidence here (search females), in classifieds, personals & online equivalents (eg, ads that limit eligibility to females), or text corpus searches revealing that the noun female referring to humans is often non-derogatory, so it all depends on the context, they'd insist that usage of the word itself is offensive, insulting, or disrespectful, and they wanted everyone taught to think that until it's the generally accepted meaning. They didn't seem to consider that promoting unconventionally sexist framings (ie, female is a dirty word) for wider adoption in our language serves sexists more than anything, and it might make more sense to resist that.