Sounds to me like your stories are excellent examples of why it can be worth playing the awkward or ‘edgy’ scenario.
Not all games have to be ‘fun’.
(Anyway, define ‘fun’).
Reading Ian Fleming can I suppose be ‘fun’, entertainment at a basic level.
Or you can read le Carre and be entertained at a higher level with insight into the human condition in extremis that most people will never experience for real.
I think you have clearly shown that there are games that may not be ‘fun’ in the Mary Poppins sense but entertain and engage at a different level. Some people like having a look into the abyss, especially if they can shut the book, or pack away the models and step back from the brink.
I don’t see self-righteousness or moral tub thumping – I see a desire for a different gaming experience than simple ‘fun’.
I would worry more about people trying to extract ‘fun’ from some situations in war that do not lend themselves to it, than people trying to explore some of the harsher realities of warfare.
I hope in the debrief on the alien game the error the killing spree people made was gently, but clearly, explained to them in a way that did not make them feel they had been made fun of but that they could take something positive from.(Being different doesn’t make you a legitimate target – sounds like a good learning experience to me).