I recall at a recent general election (2015?), The Green Party went off on one about copyright. Their cunning plan was to broadly eradicate it, because in their utopia, this would mean everyone could benefit. When I challenged Green members about this, I was told that creative people should just create new things rather than relying on earning from old ones forever. I was, to put it mildly, unimpressed. (Caroline Lucas, to her credit, actually listened. She convened a meeting of creatives in Brighton who explained why the then Green policy was shit, and it did subsequently change.)
All of which is to say you can be left-wing and liberal and still want to retain ownership over things you create, and to make a living from them. I would never, ever argue Mills doesn’t have that right. Where things become more problematic is when his arguments about creator rights are inconsistently applied (e.g. with Accident Man) and, to some (albeit not much) extent, when he’s happy writing other people’s characters but fumes when anything at all is done with even his minor players.
In short, I’m happy with more Strontium Dog appearing in the Prog, on the basis Wagner’s okayed it. I wouldn’t be thrilled if someone else wrote Sláine expressly against Mills’s wishes. (The John Smith stuff is, of course, in the former camp, on the basis of his Facebook posts, although how the destination was reached remains unfortunate.)