I agree with your argument as stated here ("this is complex because the system of legal rights is complex"). I guess your example seemed to me to be an endorsement of relying on the creators opinion and not the rights-holder in cases where they are not the same, and I was arguing against that (assumed?) endorsement. The fact that the creators are not necessarily the sellers is at the heart of a lot of pro-piracy arguments and I've often seen it used as blanket justification for _any_ piracy, even in cases where the rights-holders and creators are the same entities, so I guess I'm a bit sensitive to it.
Side note: I used to co-run a small electronic record label, and almost all of the artists who we released music by were just ourselves (with a few exceptions made for close friends, who retained all rights to their music). Given our small size and low profile, it was shocking to see how quickly some of our releases were pirated. Sometimes albums would hit soulseek after we had only shipped out the first 30 or so CDs (and no MP3s). We weren't in it for the money... it was just a side-activity while we were still in school, and any money made was just funneled back into the label so we could release more music, so fortunately the piracy didn't affect us much as far as we cared. But it was still incredibly surprising.