"I don't know when the extreme intellectual property viewpoint entered software engineering as a mainstream opinion because I have never before seen it expressed so strongly in this community"

It's not copyright maximalism, it's just bog-standard rationalization. I don't like what this company is doing, it looks like I can hit them with the "copyright" stick, so I will. One day later, I like playing abandonware games and that should be legal and copyright is stopping me so copyright bad, grrr argh.

At least, at the HN gestalt level. Individuals may say one or the other of those things from a principled perspective, but I perceive a lot of rationalization in these discussions overall.

There's not a lot people coming at this from any sort of principled position. I think one measure of that is that the modal principled position right now ought to be something fairly close to "I don't know". AI has kicked a lot of the foundation out from underneath copyright and I don't think anyone serious has more than a first draft of what the plan moving forward should be. Even if you can get two people to agree on the goals we should shoot for, which is already a tough ask even in a pre-AI era, getting them to agree on how to achieve those goals will be a long shot... and that's entirely separate from the question of whether the actions would in fact end up accomplishing the goal, which I don't trust anyone to have a good bead on right now.

Nominally, the principle of copyright has been to preserve creativity. Ten years ago we all had a reasonably similar idea what that meant, but we don't even have that now.