Saying that he's out of line or amoral implies that you have an intimate understanding of the situation and that you've weighted that he doesn't have the moral

Saying that he's out of line or amoral implies that you have an intimate understanding of the situation and that you've weighted that he doesn't have the moral grounds for doing this, which you might agree is disputable. In my opinion, the only reason this tactic is not recommendable is that it's not deemed acceptable practice from a professional standpoint, and I believe that this is mostly a cultural thing. Everybody says it's wrong, so it must be wrong. Think about it, if tomorrow all service providers developed a mindset where this kind of shaming in an attempt to collect from deadbeat clients became standard practice, nobody would be advising against it anymore. This is consistent with a lot of everyday nonsense that pass for acceptable, just because that's just the way things have always gone. I'm not convinced that there aren't places in the world where this is seen as perfectly ok and maybe even expected.