The other side is a person who is capable of rationalizing theft because it is a minor theft.
The theft isn't of an object, it is theft of compensation due to a creator. Duplication isn't the issue.
Spinning it as purely a compensation issue is being a bit reductive, IMO. And from there it leads directly into objectively unanswerable intent questions.
Also, since DNA controls what you look like, including your silhouette, you will have to pay me every time you allow a light source to cast a shadow of yourself onto a flat surface.
Also, when you take a bath, you displace a volume of water corresponding to your shape. That is an unlicensed copy.
Your footprints in the dirt or snow, ditto, not to mention the fingerprints you leave on everything you touch.
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Man, think about it. Millions of years of evolution (based on continuous unrestrained copying and alteration on a massive scale) lead to Man. What does man do? Put three guitar chords together with some puerile, hackneyed lyrics, and insist on compensation from everyone that hears the crap.
Based on my limited understanding of copyright law, it does in fact concern itself with actual duplication, and is rather mum about compensation.
You can infringe by, say, altering something that is freely distributed in a way that is not permitted by its license (for instance changing the copyright notice to say that you created that work, rather than the author). The author could be adamant that permission to do that is not granted at any price (so that it's not an issue of compensation, but purely about unlicensed duplicates with unauthorized alterations).
Breaking into a house - we have a name for that - it's called "breaking and entering" and "trespass".
However, going along with your analogy, say you're in my house - from my perspective, I would care about what you did.
If you took something that was mine, and denied it to me, I'd be quite annoyed. (I've had a expensive road bike stolen, so yes, I know what it feels like).
However, say you took photographs of everything I owned, to copy my packing style and organisational techniques? Or took them so that you could re-buy everything I have for yourself off Amazon? I probably wouldn't be annoyed, so much as think you odd...
Your example of how it's "practically" impacting your life is that if you happen to commit a felony against the person and then analyze their computer explicitly looking for it, you'd happen to find out?
I think that's the very definition of "not a practical difference in my life", given the distinctly low likelihood that series of events would ever happen.
Would you care to try again?
Arguments that it is stealing are also nothing more than rationalizations. That's what both sides wield: it's a war of rationalizations.
(I tend to be more convinced by the "it's not stealing" rationalizations myself, simply because stealing an object makes it unavailable. If someone stole my bicycle, I'd be upset. If they cloned it in a Star-Trek-style "replicator" and took the copy, I couldn't care less. If you lend a book or DVD or SD card or whatever to someone, upon it being returned, you have no way to test the hypothesis "a copy of this was retained by the borrower". Not testable is not real, for all practical purposes.)