You are implying that a few individual women you know being okay with a thing implies that it is alright / not sexist / shouldn't be offensive to other women. I'm not necessarily sure that that follows. (This is independent of whether or not the term 'guys' is sexist or offensive to women or anything else).
I will accept many corrections for the benefit of diversity, but when even the majority of the disadvantaged group uses the word in a non-hostile way, I stop feeling like I'm being asked to be helpful and start feeling like I'm being micromanaged and controlled by people who refuse to take into account the obvious intent of my words that the majority of listeners understand.
Informal plural forms
Despite you being both singular and plural, some dialects
retain the distinction between a singular and plural you
with different words. Examples of such pronouns sometimes
seen and heard are:
...
you guys – U.S.,[2] particularly in the Midwest,
Northeast, South Florida and West Coast;
Canada, Australia. Used regardless of the
genders of those referred to
...
(I live, work, and went to school in Northeastern U.S.)
If you explain your intent and they still feel offended, I do wonder how one should react to that. It feels to me like someone who is being pedantic who thinks they are "right". Who knows, maybe it does offend enough people that this usage will decline.
Well, it's judgement call, but offense alone is not enough to change behavior IMO. There was a case where a person reading a history book about the KKK in the presence of blacks was accused of harassment because the picture on the cover depicted: the KKK. That's just ridiculous.
I just realized that my wording was pretty vague. I would err on the side of not changing your attitude. I say this primarily because using one persons reaction (or even a few peoples reactions) to something you do as a test for deciding if you should reevaluate yourself would make you chase your tail like a dog: there would be no end to it. But yeah it is mostly about intent, in my mind. Disagreement is necessary but not sufficient for change.
If you care about someone, and they're offended, then you'll change your behavior.
I'd venture to guess you're also both rational adults, and you if care about someone, and they're offended at lots of different stuff (sexist language, passing clouds, the endless sea), then you could talk about why passing clouds and the endless sea offend them.
This really comes down to human decency; if you see women as people first, worthy of respect and care, then you'll probably want to minimize how much you offend them, instead of placing the problem of being offended on them.
But that right there is exactly the problem I have with people like this. Being offended is a choice. People choose to be offended. One might hear something they perceive as offensive and they're given a choice: Did this person actively choose to offend me, or am I taking this the wrong way? In one choice, you assume that most people are generally good, have good intentions, and aren't out to get you. In the other choice, you position yourself as someone under attack, or someone at the lesser end of a power dynamic.
Again, if you respect the person you're standing next to, the person who's now offended by something you've said, then you're probably going to act a certain way: you're probably going to hear them out about you offended them, and you'll probably want to apologize and then amend your behavior.
Can you reconcile "I respect you" and "I'm not going to acknowledge your being offended, but instead will tell you how you're wrong"?
If I say that an inanimate object is "sexy" and the woman nearby me feels offended by it, certainly I don't want her to feel bad, but I have to be entirely honest and feel entirely blindsided by her state of mind. If I talk about night being dangerous because it is dark and visibility is low and a dark skinned person nearby gets offended, I really have to wonder. I mean as a white guy I guess I have to assume that everybody around me is assuming the worst of me? You don't have to answer that. And I would hope that the person who feels offended would try to meet me in the middle, as it were, by evaluating their overreaction to the situation while I would try to evaluate the language I use, but seriously we are really going down a rabbit hole here.
So if your neighbor is offended that you wear blue shirts and insists that you should wear green shirts, will you change your behavior? After all, they are offended and you care about them.
In this stupid hypothetical (stupid because we're talking about the very real problem of anti-woman sexism in tech, and you're comparing it to someone having an irrational reaction to the color of a shirt), I'd ask my neighbor, "why? Why does my blue shirt bother you?"
My neighbor responds, "because the blue-shirted security forces in the dictatorship where I grew up killed my family when I was young, and it's very troubling to be reminded of that, even now."
Done, I stop wearing blue shirts.
To continue with the stupid analogy, I'm crediting my neighbor with not being irrational, and putting in the effort to listen and hear them out.
Just like I credit women, back in the real world, with not being irrational, and I hear them out about their complaints/frustrations/laments about sexism in tech.
You should follow the prevailing culture of the place you're in. On the internet, a meeting of 190+ countries, anything goes.
Certainly, my experience of America was that you guys say "you guys" all the time. The composition of the group is irrelevant. It transcends particulars.
But if you live in a subdistrict of California where "you guys" is taken completely literally, then by all means stop.