British literary critics of the 19th century had the notion of the "Young Lady Standard", which was a kind of family-friendly
U-rating for novels that would not offend the sensibilities of a Victorian girl. Because of this, British literature often shied away from the sort of forthright depiction of life you find in French or Russian novels of the time. There was a feeling on the Continent that literature was an art form and had a right, indeed a responsibility, to mirror life warts and all. In Britain literature was the forerunner of early-evening television.
Even so, authors like Jane Austen were not the twee and cosy yarn-spinners that many suppose.
Lady Susan Vernon is an amoral, manipulative adventuress who deserves a place in the ranks of dark antiheroes alongside Vic Mackey and Walter White;
Catherine Morland runs afoul of predatory sexual vindictiveness;
Lizzie Bennet takes on a real-life dragon for very high stakes;
Becky Sharp is willing to betray even those who love her just to squirrel away some cash. Nonetheless, though depths of human depravity are certainly there to be inferred in 19th century British literature, those are all
pre-watershed conflicts. None of them is described with the uncompromising raw honesty and occasional breathtaking brutality of authors like
Balzac or
Chekhov.
Dickens wrote stories to stir your emotions, but he and his readers knew they were parlour entertainment, to be read by the whole family -- a "safe space" in entertainment. A Victorian paterfamilias who opened a novel to be confronted with the likes of
Madame Bovary might well have stormed back to the bookshop and thrown it through the window.

I think something similar is behind the uproar we sometimes see nowadays over "unsuitable" content in roleplaying games. There are some people who play games the way those Victorian families read novels; there are others who expect games with no holds barred. This has led to the concept of the
"x-card" -- sadly nothing to do with
homo superior, but a mechanism to interrupt games whose scenes or subject matter a player is unhappy with. To quote from the blog I linked to there:
"The x-card is used to signal that a boundary has been crossed or that a player is not OK with the content. The game stops immediately, and discussion shifts to the reason why the card was used."
For me that's as absurd as calling a halt to a disturbing play or movie. If you don't like what you're seeing, don't tell me about it; there's the exit. But there's a category disconnect here. I regard roleplaying games as art, no different from literature, theatre, cinema, poetry, and painting. The people who advocate x-cards want their games to be morally uplifting and to avoid upsetting anybody, just like those family novels for the Victorian fireside. We have different expectations.
I have a player who doesn't like horror scenarios. If we're going to be playing a horror campaign, that's OK; she sits it out. Sometimes there's a grey area. A scenario may not be overtly intended as horror, in the sense of belonging to the horror genre, but horrific things happen. There have been a few times when my players have shocked me to the core with some of the things they're willing to do. And that's fine. It's why I play, in fact, to see those things that emerge unexpectedly from characterization -- sometimes beautiful, sometimes very nasty. It's the same when writing characters. You ask yourself how far they will go, what lines won't they cross, and the answer is often revelatory.
What do you do if you come up with something you know will be shocking, whether as a player or a referee? If I thought my players couldn't handle it then I'd keep it to use in a story, perhaps. But really, if my players were like that then we'd soon part company. They and I know we're not setting any limits.

Taking
the blog post I cited again, one of that player's boundaries is "I don't want any romance involving my character." But it's really hard to plan that kind of thing in advance, especially in the improv style of play that gives the best games. When refereeing, I wouldn't have an NPC profess love for a PC if I didn't think the player was capable of running with it. (I'm talking about their acting ability and imagination, of course.) What if one player-character falls in love with another? I'd much rather they both played it. Unrequited love is one option there, and it could develop in interesting directions as we know from countless TV shows and novels. It would be pretty disappointing if a player just said, "I don't want to roleplay that." In that case
play your blocking. Reject them, spurn their advances in-character. Don't
tell everyone about it.
But what about games in a public forum? Twenty years ago I went along to a convention to sign Fabled Lands books but soon got roped into a series of fascinating mini-RPG scenarios run by the guys behind
West Point Extra Planetary Academy. Each game had a different setting and was built as a moral quandary to be played out in twenty minutes. They could hardly have started by saying, "This scenario deals with issues X, Y and Z." It's
the trigger warning problem. If you're trying to capture a genuine sense of surprise in the game, you can't give too much away upfront. (Not to mention that
the evidence indicates that trigger warnings are of no use in any case to the genuinely traumatized.)
Why have these debates crept into games of late? I think partly because roleplaying is becoming -- well, not mass market entertainment, not by any stretch, but certainly it has opened up beyond the hardcore gaming demographic of the early days. Aficionados take a sophisticated approach to their hobby. The casual fan tends to have a less mature outlook.
Also, American culture has always had a much more censorious streak than European. The idea of shutting down a discussion because it offends somebody's moral code is perhaps natural if your country was founded by Puritans. And because of social media, the Overton window has shifted away from liberalism towards moralism. Hence
gripes like this, that maybe do make sense over in the US (American friends, feel free to chip in) but strike most Europeans as potty.
And because most roleplaying derives from genre fiction, and genre sensibilities tend to be a little less grown-up than proper literature, there's a tendency to expect roleplaying games to stick to the soft-soap forms of conflict you get in traditional SF and fantasy. Witness the outcries over
Game of Thrones when the writers stepped outside genre norms -- even though that was pretty much the entire thesis of the show from day one.
Anyway, enough theorizing. What do we do about it? Well, surely few gamers want to sit around listening while one player explains their reasons for halting the game. The next stop on that line is
struggle sessions, which nobody will enjoy. But those people's sense of offence seems genuinely to overwhelm them, and there's no point in subjecting anybody to an experience they disapprove of. So we're going to need better ways to signal which kind of roleplayer you are. High literary with anything goes, or pulp with puritan boundaries? As long as everyone around the table knows what they're letting themselves in for, I'm sure we can all keep on gaming without needing to call the thought police.