There are lots of languages where the gender-neutral term and one of the gendered terms are the same. Consider the Spanish "ellos", meaning either "the masculine group" or "the masculine and feminine group". The word "ellas" denotes a feminine-only group.
It seems very reasonable that "guys" could function similarly in English. Moreover, I might not say "the guys I've dated" as a straight man, but if all the women I've ever dated were talking together in a room, I wouldn't bat an eye asking "what are you guys all doing?".
Similarly, I wouldn't say "all the folks I've dated", but I might say "good evening, folks" -- the word is a misfit solely because of the idioms and context, not because the word is inherently communicating something else.
"Guys" tends to be neuter in the second person and masculine in the third person.
In any case, I think your example works better with a bisexual speaker. A straight guy would probably use more specific gendered language rather than a neuter construction. A bisexual person using "guys" to refer to the men and women (s)he has dated would be an example of a third person neuter usage—which I also think would be quite rare.
A nuance of that usage of "guys" to refer to a group consisting of both men and women is that the group of people being referred to is typically immediately present in some way.
Like in those earlier examples, the people are probably all within the same house/yard at the same time when they're called to dinner, or they're all using the same online discussion forum at about the same time.
When discussing multiple individuals with significant time and/or distance separating them (like the people somebody has dated over the span of years), a more specific term like "men", "women", "men and women", or "people" would likely be used instead.
The person he's responding to is choosing to be obtuse in order to police other peoples' language based on rules derived by their political ideology, and does not care about context
Glad it's not up to you to "buy" the words I choose!
My region uses "you guys" for the you plural in English, too, and you petty speech totalitarians didn't show up until I was grown so even though I now live in a region that says y'all and even prefer it, when speaking I form sentences in my native language too quickly to catch myself every time I use my native term for you plural
But you and your language policing petty authoritarians would have me sent to the gulag for your ridiculous overly academic context ignoring willful and politically motivated misinterpretation of my diction
Oh my god you are being so dramatic. Someone says something you disagree with about whether a term is gender-neutral and you're suddenly talking about "speech totalitarians" and authoritarians and gulags. Get a grip.
If everyone I dated were in a room, then I, a heterosexual male, very much might address that room as guys. As in, "hey guys, what are you doing here?"
It's an interesting bit of context. I also grew up with guys as a generic plural, but it's not really generic, rather it's a mixed group plural. It would feel just as natural to say "the people I date", as "the women I date", but never "the guys I date.
Even that's a weak rule though. For example if a girls soccer team performed really well you might hear someone say "those guys really gave it their all today" (though I'd say this usage is mostly dead, I don't think I've heard it this way in a long time), but never "THE guys really gave it their all today".
I'm sure some linguists have studied this and have a term for this kind of thing.
Why would they use it to refer to a group of exclusively women? 'guys' refers to a group of men or a group of men and women, not to a group of women. Is that so hard to understand?
It seems very reasonable that "guys" could function similarly in English. Moreover, I might not say "the guys I've dated" as a straight man, but if all the women I've ever dated were talking together in a room, I wouldn't bat an eye asking "what are you guys all doing?".
Similarly, I wouldn't say "all the folks I've dated", but I might say "good evening, folks" -- the word is a misfit solely because of the idioms and context, not because the word is inherently communicating something else.