I did read and fully understand your comment, and no, I don't think you've addressed the point in my comment. However, I do agree you've suggested a subtler issue than the one usually discussed in this context, and since my comment used terms like "scarcity" and "infinitely copyable", I may have come across as endorsing a much more simplistic argument than I intended to make.

You described the idea of taking a physical item and paying only the manufacturing cost of that item, and I'd assume you intended that to define copying a file as taking it and "paying" the copying cost of 0.

However, those two actions still have a fundamental difference, and not one of price. Assuming a price (zero or otherwise) also assumes a particular entity owed that price; the analogy you made assumes a price inherently owed to the original author of some piece of data, and that copying the file amounted to refusing that price and choosing to pay 0 instead. When I disagreed with that analogy, I didn't intend to imply that the zero cost of copying data provides a justification; rather, I disagreed with the implicit assumption of inherently owing any particular price to the author (zero or otherwise).

To elaborate on that distinction: if I want to copy a chair, I can look at it, perform measurements of it, perhaps perform some materials analysis, and given sufficient skill I can make a copy of it, all without affecting the original. I argue that I have the inherent right to perform that process. That process will almost certainly entail some cost to me: for instance, I'll have to purchase materials to build the copy. However, I don't inherently owe any price to the original designer or builder of the chair, beyond what I might have originally paid them to obtain the original chair. I'd consider the copying of a chair in this manner exactly analogous to the copying of a digital file in all relevant respects. As it turns out, copying digital files requires no particular measurements, materials analysis, or skill, and costs effectively nothing; however, that particular detail doesn't matter for the question we've both asked, namely "does the copier inherently owe anything to the author". And if we build a system to automatically analyze the chair and print a new one on a 3D printer, and can thus copy a chair at minimal expense, that doesn't affect the key question either.

Bringing that back in the direction of copyright, the same thing applies to the copying of a physical book: that process typically involves a non-zero cost, in some combination of time, wear on equipment (copier, scanner, etc), and possibly materials (if copying onto paper), but the conclusion remains the same.

And to go in a different direction: if I hear a song, and later sing it myself, I've copied it (lossily) with my brain and vocal cords, at zero cost to me and zero inherent price owed to the singer or author of the song. We've had infinitely copyable goods long before we had computers.

If you take a bag of M&Ms and pay less than the cost, the proprietor of those M&Ms no longer has them, and cannot then choose to do with them as they see fit; I'll assume from your use of that analogy that you already agree that such an action violates basic expectations of property rights, and that the proprietor of the M&Ms can choose to demand any particular price or none at all. I agree with you completely there: you don't have the inherent right to steal a bag of M&Ms because you find the price not to your liking. However, I hope I've made it sufficiently clear why I don't find that situation analogous to copying a file, or to copying a chair, or a book, or a collection of sound waves.

However, your analogy does actually suggest a rather clear approach to handling trade secrets, or (as brought up by another reply to my comment) private information. If someone chooses not to distribute certain information at all, then taking it from them against their will does not seem reasonable to me. For instance, if someone breaks into my personal system, copies my passwords or encryption keys, and distributes them to the world, I don't consider that reasonable, despite the copying occurring at zero cost; that situation seems quite analogous to the one you described.

That seems like an entirely different situation from the one more commonly addressed by copyright, namely the original author choosing to distribute information and then attempting to control the subsequent distribution of that information by others. I'd argue that the author has every right to choose what to do with the information they have, including not distributing it at all; however, if they choose to distribute that information to others, I'd also argue that those others have every right to choose what to do with the information they have, including distributing it further.

Hopefully I've managed to make it clear that my comment came from a position of careful thought, not from a pattern-matched knee-jerk reaction. :)