herongale: Reality is reality and fiction is fiction

That's part of what you said. It is not that simple. Fiction exists in the real world, and influences real-world people. This is not an issue of "some people" not being able to distinguish between fiction and reality. Even if everybody were able to do so, this would still be an issue. Language influences people. Fiction influences people - and not just those mythical creatures who can't distinguish between fiction and non-fiction accounts - and a strong version of my claim here is that no one can.

Your claim seems to be that since because fiction is fiction, it is somehow less harmful, because it can't be taken as seriously and it is not reality. But how much of what you write is fiction? What you write is informed by your real-world experiences, too. Are houses fictional? No. Is it fictional that people have heads and arms? No. Is it fictional that gay people exist? No. What else is fictional, what mirrors your own experience with gay characters? There is no way to draw the line, even for people who are very well capable of distinguishing fiction from reality.

The narratives you come across organise your thinking, and if you come across one particular narrative over and over again, it is difficult or even impossible not to have that part of your narrative enter your brain and become the definitive narrative. This is my problem with a majority writing a minority. M/M, as I am told, is a genre by and for straight women - it influences their narrative of what gay men are like.

It is common knowledge that advertising is fiction, and still it is as commonly known or suspected that advertising can have a very direct negative effect on the self-esteem of women. Fictional stories in which women are presented as flat characters only there for the gratification of men, like porn movies, are questionable, because they present men and women alike with scripts of sexuality that are unrealistic, but still change the narrative of what sex is "supposed to" work like. This is not conscious, no one sits down and goes, "Oh, I'd like to watch a movie in which women are objectified right now!". That, in parts, is the problem, and if this were what people are doing, this would be less problematic.

Now, with the stories written by straight women and informed by their experience as straight women which are about gay men, the problem I see is that they start replacing the narratives of and by gay men about gay men for the women who read these stories (simple because there are so many straight women who write these kinds of stories - from my experience, though this might be wrong, even more than queer women). There are, as it is, many negative stereotypes of gay men permeating the media which are influencing people's narratives of what a gay man is. This is another one that cannot ever be accurate. So yes, I believe that all stories written my people who are not a member of a minority about a minority are appropriative to some degree, and I believe that romance stories which strongly focus on an idealised version is especially appropriative.

What I want?
I want more self-reflection, self-awareness and critical thinking skills for both readers and writers.
I want people to examine their own reasons for writing what they are writing, and
I want readers to examine for what reason they are reading it.
I want genres about minorities to be dominated by those minorities instead of majorities - I want more original slash fiction about gay men to be written by gay men than by straight women.
I want the story of the minority people write about to be the definitive story.

I want you, herongale, to ask yourself, "why am I writing slash? What does it do for me that other genres don't? Why do I find the tales of two men together more interesting than others? Why is it ok for me to appropriate another person's experience for my own ends?"
And I want your readers to do the same.

I'm genuinely curious what people say here, by the way. I know that there are reasons that are therapeutic writing-related, but I am curious what other reasons there are.

And I am not saying to anyone that they are not allowed to write whatever they want, because of course they are, but I don't want them to get away with it easily if it seems that they are writing about an other without reflection of why they feel it is appropriate to do so.