It's clear that one is a mirror image of the other with minor Photoshop edits. I think it's clear to just about everybody. I don't believe you are arguing in good faith.
IANAPS, but I don’t think these are minor ps edits (or that it’s even ps) after overlaying the two and sliding the opacity. That’s a grey area no doubt, and the source of “inspiration” is clear, but you’re probably overtrivializing it.
I don't think the claim is that it's literally Photoshopped. It's a painting. It could be a painting of a Photoshopped version of the photo, or the changes could have been made while painting. There isn't any legal basis for distinguishing between digital and physical works here -- a copy is a copy, and a physical copy with alterations is as much a derivative work as a digital copy with alterations.
Would you consider an oil painting that exactly duplicated the photograph to be sufficiently different to not be covered by the original artist's copyright?
I think if the painting were perfectly identical than it'd be just a reproduction and it should violate the photo's copyright, but even if such a thing were possible for a very skilled artist to pull off, I don't think that'd be something that happens very often. I'd guess that most artists would have a hard time not making changes.
We want artists to be protected from outright reproductions of their work, so that'd include minor low effort changes in photoshop made just to get around copyright. Artists should be free to create their own versions of existing works though. Copyright is supposed to encourage the creation of art after all.
OK. You should make it clearer that you're arguing for a weaker system of author's rights, not just making claims about the current system. I favor copyright reform but what you're suggesting would destroy the ability for artists to commercially exploit their work.