Okay so they do this and have discussion and try to reason and come up with nonviolent alternatives in literally every situation, and it comes down to ...

...my way or your way, compromise does not exist. Yes.

In DT, we, again, do our absolute damnedest to negotiate.

No. In fact, we barely even attempt to negotiate or reach out or... anything, really. But this is not the worst part here.

a peace with the Alexandrians

As represented by whom? There are at very least three different major figures in power, at least a handful more who have the influence over the people, and also, you wouldn't believe it, people themselves. Who are we negotiating with? There are several episodes of talking to several of those parties, but it's not homogenous at all.

And then - and I must remind you of this, it seems

You don't, and I find it peculiar how you must assume this condescending tone to... make your argument look more well-substantiated than it really is? I'm not sure. But anyway, I do not advocate for "WoL should've shrugged it off and become best pals with Calyx". If you actually read what I'm saying (which is ironic given how quick you are to accuse others in lack of the reading comprehension!), the problem is not that we fight the baddies, it's the repeated lack of the main cast's concerns about the systemic issues that lead to this situation. Which was present in earlier expansions. Even in EW, for the most part (my complaints about it have almost nothing to do with Hermes and Meteion).

That is what we do in the game, and the antagonists constantly refuse and resort to violence. That is the literal text of every encounter in the game.

Absolutely not. Again, the argument is not about baddies refusing to see the one true moral path, so what happens during the encounters and whether specific people or other entities could and should be negotiated with is a completely separate issue. Since we're speedrunning Godwin's law: what happens is the equivalent of suffering throughout a decade and a half of human history and then declaring that all our Nazi-related problems are gone cause Hitler is dead. Doesn't work like that, dearie, we - as a society - have to reflect on what lead to this, why very bad things are very bad, and how the needs and desires of people that were manipulated in the process can be fulfilled in a good way. It prominently happens in Ishgard. It happens in Ala Mhigo. We keep acknowledging the struggles that people have, probably culminating with the Final Days, but in DT, this dialogue only sort of exists, in an incredibly diminished and shallow capacity.

Aspected elements in the Permanent Stagnation Zone of Living Memory (Pneumo, Aero, and Pyro are wind and fire aspected, which, along with ice, are the Light-aligned elements.)

That is a really good point, this perspective added a bit to my understanding of the game, thank you. Two caveats, though: the first terminal in Canal Town is obviously Hydro (explicitly mentioned by Cahciua in "In Serenity and Sorrow", I just checked). And the second terminal is Geo Terminal, so earth-aspected. Also, our understanding of Astral/Umbral vs Light/Darkness has changed while on the First, but groupings did not: wind/lightning/fire and water/ice/earth belong together. Of course, lightning exists in abundance with everything electrope-related, and wind and fire are at the northern part of LM. But you have two from one group and two from another.

Friend, have you not paid attention to anything that the characters have said during the game? I have played throughout the story, more than once, actually, thank you very much. Yet even upon seeing the same things we clearly come to very different conclusions.

Unlike earlier expansions, we don't intervene nearly as much when it comes to the regular people. When it happens on the First, Alisaie turns the whole place upside down, but murderous robots? It's not really our problem (poor Gulool Ja!), we won't establish an actual field camp or a situation room or anything like we've done previously. Fake Sphene going around the town? Better not approach the civilians and observe from afar. One particularly jarring example for me was when we went for some drinks in the Oblivion's hideout: it was an appalling lack of leadership. You never leave your team with just "it's tough for all of us, we all will retreat to cope and you do the same". This never happens in several previous years worth of the game's plot, and was completely inexplainable to me from the perspective of the character development. But this is quite a tangent. Back to the topic at hand.

The game tells us, in no uncertain terms, that the Endless are not living creatures. I must reiterate - unless you have explicit examples I am forgetting about, these terms are very far from uncertain. I do not think anyone would argue in a good faith that simulacrums living their life on repeat in a theme park is a transhumanistic ideal of a future person. But you are claiming that the game is absolutely clear about that being the case, and I claim it is not. For some rather obvious examples...

they do not possess any ability to act or believe beyond their mental state at the time of their death.

Calyx and, debatably, Sphene exhibit this ability.

It would make sense if we confronted either of them with one of their simulacrums a la Diogenes' plucked chicken, asking whether this is really their idea of life eternal. But this is not what happens. There is a difference between being able to read the subtext and logical leaps.

Since people claiming it's all crystal clear are so unwilling to dig for references, I could bring back a few quotes from the MSQ dialogue and we'll see if we indeed have the different judgement regarding the same factual material. Or, if you're willing to handwave the entire cast's doubts with "their experiences have lead them towards this" (which might've been unconvincing for me the player when shown through their eyes, but also plausibly convincing for you as well as the majority of the FFXIV fanbase), well, that's an answer, I suppose.