This is the true reason why violence is allowed on TV, whereas sex is always problematic and often censored. You can watch violence with just about anybody (kids, parents, etc.) and it doesn't feel awkward.
It's typically made very clear to everyone that violence is wrong, and what you are watching on a movie or series is fictional violence. In other words, you are watching something that no one would like to go through.
Sex is fundamentally different. As it is not only desirable in many senses, but it is also a basic human function, but at the same time it is something extremely intimate, not something you share with any random person.
That’s cultural - our reactions to violence are pretty fundamental, too, with roots deep in our brains. It’s natural to feel empathy for someone being hurt, to appreciate the implications of them being hurt or killed, etc. The difference is that our culture says that’s okay to show children, so most of us are at least partially desensitized during childhood.
Broadly speaking (many exceptions), Americans are fine with young teens watching a movie about a man using kung fu fantasy tactics to bloodlessly shoot his way through a building of bad guys, like John Wick, but don't necessarily feel the same way about something that depicts violence in a more brutal and arguably realistic way, like Saving Private Ryan. Is there a little puff of red CGI mist blood coming out of somebody's chest, or does the movie show one of the 'good guys' with half his skull blown away? These are both hardcore violence in a sense, but most people see a large qualitative difference between the two.
I think it basically comes down to how likely a movie is to give people nightmares, which of course is a function of desensitization. The American public is broadly desensitized to unrealistic violence, but most aren't desensitized to realistic violence.
Incidentally, Saving Private Ryan has a lopsided depiction of violence. The deaths of Americans are shown to be gruesome and agonizing, while the deaths of Germans are mostly shown to be relatively quick and clean: https://www.youtube.com/watch?v=l4FeyONCtfc I re-watched Saving Private Ryan after watching this video and found it to be very apparent, but it wasn't apparent to me the first time I watched it.
I generally agree with your point but this has changed over time. For example, showing someone getting shot in combat was generally acceptable before torture or maiming since we’re more likely to say that those are never justified. Someone who grew up in a culture with public executions and punishments might have a more situational view based on whether it was “deserved”.
To me, clearly there is a huge difference between tv and in person. I've never even seen a dead person (except in movies).
Usually this has a bad connotation, that's why I interpreted what you said the way I did.