Props to OP for answering so gracefully, but I'm not going to answer gracefully. It is more important than ever to call out fascism whenever you see it -- especially the quiet, soft, poisonously insidious kind that Anon is practicing here.
Anon ostensibly wants to know: "Do authors realize that they're writing about things that some people might find disturbing, horrific, upsetting, repulsive, or simply just TMI?" (Yes, obviously they know. Authors are not stupid; that's usually a requirement of the job (not always. But usually).)
But what Anon is actually asking is, "Why don't authors stop themselves from doing a Bad Thing? Why doesn't anyone else stop them?" The assumption underlying that question is: "Surely if they realized that they were doing something disgusting, they would stop immediately." Even more covertly implied: "I think writing about certain things automatically taints you with moral degeneracy--that is, it marks you as a possible or potential criminal."
To that I say: My friend, writing is just thoughts copied onto paper, and thinking is not a crime. Only actual actions can be crimes. What does it matter what other people think about? Literally so what? Why do you want people to be stopped from thinking about those things ("did their editors ever gently ask them...")? Why do you care? Do you feel that an author should provide a list of justifications and excuses before it's permissible for them to write about something? Why? And who do you think should be in charge of that? The government???? YOU???????
To any person reading this post: If the above questions are personally upsetting to you, if you find yourself huffily thinking something like, "Well, I care because it could normalize--", NOPE, STOP RIGHT THERE. 🚩🚩🚩🚩🚩 This is a big red flag: You (much like the Anon) are exhibiting some early warning signs of Fascism, and that is not something to take lightly in the current political climate. There are some drugs you shouldn't experiment with even once, and fascism is one of them. Repeat as often as needed: THERE IS NO SUCH THING AS THOUGHTCRIME. WE DO NOT LIVE IN GEORGE ORWELL'S 1984.
But we already talk about thoughtcrimes now and then, don't we? I can't remember seeing someone talking about crimestop (also from Orwell's 1984):
In the Newspeak vocabulary, the word crimestop denotes the citizen's instinctive desire to rid himself of unwanted, incorrect thoughts (personal and political), the discovery of which, by the Thinkpol [Thought Police], would lead to detection and arrest, transport to and interrogation at Miniluv (Ministry of Love). The protagonist, Winston Smith, describes crimestop as a conscious process of self-imposed cognitive dissonance:
The mind should develop a blind spot whenever a dangerous thought presented itself. The process should be automatic, instinctive. Crimestop, they called it in Newspeak. . . . He set to work to exercise himself in crimestop. He presented himself with propositions—'the Party says the Earth is flat', 'the Party says that ice is heavier than water'—and trained himself in not seeing or not understanding the arguments that contradicted them.
Moreover, from the perspective of Oceania's principal enemy of the state, in the history book The Theory and Practice of Oligarchical Collectivism, Emmanuel Goldstein said that:
Crimestop means the faculty of stopping short, as though by instinct, at the threshold of any dangerous thought. It includes the power of not grasping analogies, of failing to perceive logical errors, of misunderstanding the simplest arguments if they are inimical to Ingsoc, and of being bored or repelled by any train of thought which is capable of leading in a heretical direction. Crimestop, in short, means protective stupidity.
Read that twice, and then reread the Anon's question. Translate it through that lens: "Why," says the Anon, delicately disgusted, "are these authors not practicing better crimestop? I practice it all the time. Why aren't they?"
Great question, Anon. Why AREN'T they? Turn off your crimestop and give it some real thought.
(Hint: If the answer you come up with is "Because they are moral degenerates" or anything in that neighborhood, you are unfortunately still doing fascism. Try again. If you have tried several times and the only answer you can manage to come up with is a still a synonym of "moral degeneracy" then this is above my paygrade and I would recommend talking to a trusted grownup, a therapist, a spiritual leader, or possibly your least-online friend.)