You've got a very 2D picture of this person and the situation, which makes sense, this is a text chat, and I haven't spent hours detailing my life, their life, and the relation between. But give me the benefit of the doubt.
Some additional context, normally they don't have access to their earbuds in the contexts we hang out, for whatever reason. The only difference is the earbuds. They were still half listening to the conversation, chiming in infrequently, not being standoffish, just distracted and removed, for no good reason.
And yes, in the context of "the purpose of our gathering together at this time is to socialize, and eat lunch together", I absolutely would feel the same way about someone choosing that time to read a book instead of interacting with the group. That logic is exactly what I'm talking about.
I'm far from alone in this thinking, heck, there was a meme a week or two ago about how nobody can hang out these days without everyone sticking their noses in their phones the whole time. Same thing.
Again, I wouldn't be rude to the person in either case. I'll gently try to interact with you for a bit, as a subtle cue that you might be doing something... Abnormal. But nothing more than that.
Nice way to casually dismiss my points there. That's fine. Yes in my opinion, as I've stated plainly, the way things were in this specific area, used to be better, in general.
The new way, as you've made clear, is very me-first. I can understand why that appeals to people, I just disagree with it being the correct way, or the kindest way. And I think society will be worse off for it, in general, in the long run.
But I think we've fleshed this out enough. Agree to disagree. I wish you well in your future endeavors.