It's a similar argument I heard Larry Hama make when he said the 80s GI Joe cartoon was "morally bankrupt" for depicting violence without anyone suffering from the natural consequences. For those who might not know, Hama wrote the 1980s GI Joe comic and most of the bios for the figures sold by Hasbro. The comic book was quite different from the cartoon and when the Joes or Cobra shot at someone they might actually injure or kill them.
Around here (Netherlands) the Dutch version of the comics and toys started in 1987 (I would have been 11), possibly a little earlier the cartoons via UK channels in saturday/sunday morning cartoons. At age 7-11 I really didn't need my cartoons besmirched with reality, thankyouverymuch! At the time we still were in a cold war, Europe was split in two (the wall was
maybe 250 miles east from where I lived), etc.
Even the translated comics that came out were 'The Special Missions' series (not the mainline Marvel comics), a bit grittier then the cartoons. It was only later until I got my hands consistently on the American Marvel comics (around #100) in probably 1990-1991, at age 14-15 I could start to appreciate the more gritty comics. Heck #109 had on the cover "
BODY COUNT: [7] AND CLIMBING!"...
As a child I did not need Kill Bill levels of violence in my entertainment/hobbies! Nor did I want or need it in my early days of pnp RPGs. Sure, we had some computer games with some very explicit gore, but they were NOT the norm, nor were these games our favorites.
Was G.I.Joe initially a story about describing the horror world of violence? No! It was Hasbro reactivating the G.I. Joe IP and brainstorming with Marvel to make toys for children, including an animation series... From Hasbro's perspective, it would always be about toy/cartoon violence, no matter what Larry Hama later thought or wanted. He worked for Marvel, and they sicked him onto Hasbro/G.I. Joe. And to be honest, I always saw the comic line and the toy/animation line as two separate universes that shared similar designs and organizations. I liked each at different times of my life.
I do remember watching an anime at one point when I was sick and home alone, one of the main characters committed suicide. I wept in grieve (which is very rare for me). That was an experience I could have done without at that age. And that's from someone who prefers fiction strongly over reality! When I watch a movie based on RL acts, I can get pretty angry with the world. I don't have to watch a movie/documentary about the concentration camps in WW2 for me to imagine those enough to make myself sick from the non-gory descriptions in the history books. I can also very well imagine what a fantasy sword would do to a fantasy person or monster in our shared fantasy world in particularly gory detail if I allow myself to. But why the heck would I want to?
Generally when we play D&D we don't play because we want to experience the horrors of violence. And depending on the story/setting, more or less horrors of violence is appropriate in our group. I remember back somewhere in the 3.5 age (2000-2008) I did an experiment of "At which point do the players tap out of my constantly escalating gore descriptions?", I ramped up quickly, and they quickly tapped out. When I bring that up now, ~20 years later, they don't remember that at all as something they balked at. It's either suppression of that memory (as it being to much) or has it become so normal, that it's not worth the memory?
Don't get me wrong, when I'm in the mood I'm perfectly comfortable to watch a fictional movie/animation with lots of gore/violence, and it's consequences. I can appreciate a 'good' action sequence just as much as I can appreciate a good story, but when the gory consequences don't do anything for the media/story, why have it at all? To be honest, I don't really watch the MCU movies for the stories, neither did I read the Marvel comics for the stories, it was for the illustrations/designs and the spectacle.
If my players want to murder helpless foes, I'm not going to sugar coat it so, when my nephew's cleric joined in the slaughter, I mentioned the mace caving in heads. My brother thought that was a bit much. I just shrugged -- he's the one one that encouraged this course of action, if he doesn't want his kids involved in this kind of violence, don't suggest that course of action.
Are you raising your nephew or is your brother raising his son?
You ignoring him is... Inappropriate at best, and a good reason for a parent to keep their kids away from you. It's not solely up to you to expose your players to your perspectives, but that assumes that your players have enough agency/age to make their limits clear to you. A young nephew that is still a child does not, and that's why we have parents.
And there's gore (as you described it) and consequence, what happens in a world when you kill someone. You could easily get one without the other.