That approach is limited, though.
It is limited, but only in the sense how graphic the portrayal is. One of the basics of horror (not the gore and jump scares that somehow passes for horror these days) is to use a light touch. In writing, they say "show don't tell." In horror, you want to show, but you only want to show so much.
I often compare it to sexiness. Sure, nudity is sexy. Making the comparison to horror, nudity is the gore dripping monster finally lunging at you to make the kill. However, less is more. If the graphic depiction is theoretically comparable to full nudity, then a little bit of skin here and there is like catching glimpses of the unknown from the corners of your eyes. It creates the buildup that makes the conclusion all the more satisfying.
BTW, I didn't mean literally censor things by saying "bleep", . . .
I know it's funny and a bit silly, but that was actually what I was picturing. I was picturing you, as the DM playing an NPC, telling the PCs what happened. Then, a cell phone slowly rises into view and emits a loud, long beeeeeeeeep that covers up the truly graphic parts.
Maybe that's the part of me that loves a good laugh, but that's literally what popped into my head when you mentioned censoring with bleeps.
. . . but more the general idea that "you spend an hour hiding in the rocks observing the orc warcamp, and hearing the sounds of unspeakable cruelty and orcs glorying in pain and degradation on their captives. At the end of that hour you have gathered valuable operational intelligence, and you could gather more, but every instant you spend listening to those cries drives you closer to wracking sorrow or even madness. Do you retreat or take action?" Describe the gist but not the details. I think the gist is important though, to make it emotionally clear that mercy to the orcs is not a mercy to the larger world, and that even well-roleplayed PCs should expeditiously remove them from the Prime Material plane instead of trying to be humane.
Sure, but as you mentioned, it's about the level of detail. Your quote works just fine, and it has the added benefit of allowing each player who hears it to fill in the gaps with the behaviour they find cruel and denigrating (again, relating back to the horror concept that nothing can ever be as scary as what the watchers/readers imagine, because their thoughts are tailored by their own sub/conscious minds).
It would be quite another thing if you graphically described what was occurring, if you were imitating the grunting sounds that are typically associated with violent thrusting, or if you handed out still pictures from Hostel or some other slasher film that focuses on graphic dismemberment.
D&D is a game of solving problems through direct application of violence, and that works best in a dark and gritty world where horrible things happen and someone needs to stop them.
I agree that D&D can be that. I may even go so far as to say that what you are describing is the typical means of play, but I wouldn't paint it as being as definitive as you have. One of my favorite and most rewarding campaigns focused on courtly intrigue. That campaign had a much heavier focus on skills, social interactions, and non-lethal combat (i.e. dueling) than most other D&D games I've been a part of.
Again, my campaign has lots of BBEGs bouncing around plotting against each other, and I'm still trying to figure out ways to make my PCs realize that all of them are bad, even the ones they are temporarily working with. (E.g. they negotiated with the vampire necromancer, and he ended up offering them an alliance against the 8000-strong hobgoblin army... and he is a very effective ally and will eliminate large portions of the hobgoblin army, unless the Red Dragon ambushes him first. But he will do so by infiltrating the camp, charming hobgoblins and turning them into vampire spawns, so if the PCs let their ally do his thing they will soon find that their kingdom has been overthrown by an insane vampiric warlord with thousands of vampire spawn minions... and I need a way to make it clear that this putative ally of theirs is truly baaaad news, not a morally ambiguous antihero.)
That may be an issue of the players/PCs deluding themselves (sometimes people just don't want to see things), or of the players/PCs being content to let the situation stand as long as the conflict is evil-on-evil.
Regarding the vamp though, there is certainly the question of its longevity. How long-lived is it? If it is old enough, one good way to show the PCs it is bad is to have had a vampire hunter escape with one of the creature's journals many years ago. The creature may consider the journal destroyed or forever lost, but enough of it could still be legible that the PCs can piece together how bad the vamp is from reading about its past plans that it has currently abandoned (or at least put on the shelf for a century or two).