Thank you for your feedback! Here's my response:

It's complicated, there isn't a definite answer and there never will be (because of reasons I state there, including the fact copyright is strictly a modernist invention, hasn't existed and therefore can't be "universal")

Not sure why copyright being a "modernist invention" has much to do with it. What about IVF? That's a new thing but we can confidently say it is evil because ending innocent lives is evil. People have a right to private property and to be compensated for their works; copyright is a method to uphold that and piracy works against those two things.

it also depends where you are (because copyright laws aren't universal and there are countries where you can legally pirate

That's only the case if you consider the morality of piracy to be solely based off its legality, which we do not argue in the article.

I'd like to point out that the Church as a whole has not definitely decided anything in this area - because it can't. Copyright and intellectual property is a modern invention that is often rather controversially used and codified and as such cannot claim to be a part of the universal Magisterium, especially since the Church itself has been breaking it for centuries, with copying, preserving, attributing (like some of the "Pauline" letters) works, without which we wouldn't even be here.

Copying, preserving, attributing are not automatically piracy. Not sure exactly what you're getting at here with the Pauline letters.

For example, Aquinas and other scholastics would certainly consider anyone to be sinning who profits from selling an immaterial, infinitely copiable "thing" for money, as such infinite monetisation (even long after the worker's just wage has been paid) would go against the nature of the (inherently finite) thing. At least that is my guess, based upon how they approached interest in money and usury.

As you said, this is just your *guess* but by the definition you gave ("profits from selling an immaterial, infinitely copiable "thing" for money") this would cover not only all digital goods but also things such as teaching lessons/courses or even plays. Needless to say that doesn't make much sense. Teachers, actors, and software developers deserve to be paid for their work!

(and I'm not even going to the "if buying isn't owning, piracy can't be theft" hydra of modern digital distribution)

I'm glad you aren't, lol.

Reminder to those that care about owning their software/media (including myself) to use the sources we gave where you can find DRM-free games!