Erin Palette talks about guys, and she means to include herself:
One guy is always male. (Which isn’t surprising, since Guy has been a man’s name for over a thousand years.) Therefore it follows that if someone says “It’s a guy thing” or “Guys’ night out” you know with 100% certainty that said guys are male.
But I have seen a woman address a group made up entirely of women with “Hi guys!” in which case those guys are now 100% female. However, even though a group of women can be called “guys”, I have never seen that group subdivided such that one woman would be a “guy”, regardless of how logical that might be.
This isn’t exactly egalitarian: except in very specific circumstances, groups of men are not referred to as “girls.” Still, it’s an interesting evolution of the language:
Many women feel that the word “mankind” is sexist when used to refer to all humanity, but I have yet to see any woman seriously object to “guys” even when used in nearly the same way.
I don’t really have a point to this other than Huh. A distinctly gendered noun has become a gender-neutral collective through cultural drift.
Now I wonder what the non-binary among us would think about this.