Stereotypically, women always strive to look as young as possible, so calling one a girl can be seen as a compliment. While men, stereotypically strive to appear mature, hence calling one a boy can be considered an insult.
I don’t disagree with you that society does think that way, but I disagree with the sentiment so much.
I’m 33 and afab. I accepted being called a “girl” until I was about 23 (probably not a coincidence that that was the age at which I graduated college), but it started chafing at like 16, even though I didn’t have a good alternative at the time (because I agree that “female” as a noun feels gross). If someone called me a girl now I would correct them without hesitation in basically every scenario outside of a eulogy or wedding speech.
I really wish there was a better option. I don’t really like “woman,” but it’s better than gal, lady, dudette, chick, or girl imo. I’m perfectly fine with guy or dude, especially in plural, but I’m probably an egg, so that colors my perspective for the singular use a little.
I honestly don’t see this changing any time soon because there are biological incentives behind both stereotypes. And, anecdotally, my gf (40+) will pout if in some context I refer to her as a woman, and be like “noooo, I’m a girl… :(”. Semi-jokingly, of course, but only semi.
Same as the other reply, I don’t disagree. Do I think there’s mal intent? Nah. But I’m sure this has an unconscious effect on how we perceive women. Besides lots of women look young without even trying, I think with the improvement of medicine and public health, people in general are just looking younger nowadays so we should nip this habit in the butt.