Puritans, who believed that sex was sinful and suffering was noble.

The likelihood of something happening in real life. Most people will live their whole life without getting into a violent situation, which keeps it a fictional one, but almost all will be confronted with a sexual one. Violence in media will not beget violence in real life, generally speaking (if it did, given how much violence there is in video games and movies, we'd have a Problem), but sex in media will normalize it. Or that's the theory anyway.

Another one: Sex is always happy, a happy relationship, people looking pleased with themselves after the saxophone-music-pan-out smoking a cigarette (to invoke the 80's trope). Violence is almost always bad, the hero in agony, the bad guy coming to a gruesome end (falling off Nakatomi Plaza, into helicopter blades or a jet turbine, getting roundhouse kicked into defeat, etc), etc. It's a punishment, whereas sex in a film is depicted as a reward. Generally speaking.

I would recommend it to anyone but don't think it's just a laugh.

I'm trying to think of a movie where so graphically murdering a real human with a real weapon wouldn't get a frown and an R from the MPAA like nudity would.

Kind of ironically, though, one way to dodge harsher ratings for violence is to kill non-humans (like aliens) with made up weapons (like phasers) and show no gore while doing it. Everyone has viscera, after all (I assume, maybe some aliens in the Star Trek universe don't); is seeing it such a big deal?

Most movies and shows have become so violent that I don't even look for new stuff anymore.

There are a lot of new movies and shows out there (including new Star Trek shows), especially considering how there are so many platforms distributing new content. I'd venture to say most of them are at the violence level of Star Trek or below. It's totally fine if you want to rewatch the same stuff because you know you like it, but to write off decades of new media like you have, without even seeing it, is kinda lazy.

You mean the new Star Trek, right? Because the new Star Trek is much more violent than the old, TNG/DS9/VOY/ENT shows. Not just overtly violent, but also psychologically violent. It's disgusting, frankly. And the difference is, while I'd happily show my kid the old Star Trek when they hit 7-10, there's no way in hell I would let them anywhere near close Picard/Discovery at that age.

No one wants to watch people getting it on with their eleven-year-old. An adult rating makes an easy warning.