On Problematic Tropes

I have a couple of conflicting principles that I don't know how to reconcile:

* Fiction at its best illuminates reality. This includes all genres, even the obviously fantastic and implausible. Fiction has the ability to make us understand one another better, to let us see through another's eyes. This is amazing and powerful and should be used wisely.
* Daydreams and fantasies are harmless fun. Fantasizing about things that are unrealistic, as long as you know that they're unrealistic and have no interest in making them reality, is fine.

There's no conflict between the two when one's fantasy is something socially-acceptable if impossible, like "having a telepathic bond with a friendly dragon".  Things where, if you could make them real, it wouldn't be particularly detrimental for the world at large.

But lots of fantasies are not socially-acceptable, nor a desirable/plausible reality. Twilight, for example, gets a lot of flak for its romance between a century-old vampire stalker and his 17 year-old love interest*. There's a novel I won't name about a romance between a Nazi concentration camp commander and a  Jewish prisoner that ends with him rescuing the internees and her converting to Christianity. Master/slave romances are commonplace.

I've named all romance tropes here because those are the ones I hear discussed. Maybe in horror circles they discuss whether their monsters are too monstrous or the events depicted too awful, and I just don't hear it. I hear occasional decrying of the Chosen One trope of fantasy, or more rarely, on the idealization of feudal societies and tyranny.

In general, I am talking about tropes that entertain but appear to do the opposite of illuminate: dehumanise, debase, disinform. Tropes that turn things that are devastating and awful in reality into light entertainment, or portray those things as acceptable and even enjoyable in the context of the story.

I believe in free speech, so obviously I think people should be allowed to read and write what they please regardless of whether or not I think it has merit. That part is easy.

But when I run into a trope that deeply offends me, I feel this conflict over whether or not condemnation is appropriate. How dangerous are fantasies? Does it make a difference if you draw on real history or use a fantasy world for the setting? (Eg, would the Nazi/Jew romance be less offensive if the same tropes were used in fictional countries with fictional religions?) How much does tone matter? I can't help thinking that tone has an impact, that some things are written as escapism and the author and readers are aware that it's Not Realistic, and that's different from a book written seriously. From one where the author's style suggests "this book is illuminating, resonant, true" and I am all D:

But I don't know. Maybe what I want is a bright line between someone's goofy dubcon fanfic and a mainstream novel glorifying rape, and maybe there can't be one. Maybe judging works case-by-case, and recognizing that what I think is offensive and repugnant may be someone else's harmless fantasy (and vice-versa) is inevitable.

I remain curious about how other people feel on the topic: Of the principles I opened with, do you find one one or the other unconvincing? If both are relevant, how do you handle the conflict?

* On this subject: I half-joked last month that 'I'm not saying it's not possible to write a good romance between a first-person young woman narrator and an ancient superpowerful male jerk. Wait, maybe I am'. But I remembered later that there's a book I liked which used this trope! N.K. Jemisin's The Hundred Thousand Kingdoms. So yeah, apparently I judge based on execution as well, even when I feel strongly about the trope.