Those authors clearly show they don't have any human experiences to draw from, so to expect them to portray human behavior accurately is a huge stretch. Even if they do, there's no commercial incentive to portray it accurately.
This author in particular clearly is self-aware enough to satirize ntr, but if you look at his other works, he handles women's trauma in a very unrealistic tropey way to the benefit of the target audience.
I think OSP had one of their superhero diatribes mention something related to this. I don't remember what they called it but I always referred to it as 'literary inbreeding'. The original superheroes were responses to very specific real world problems but the following generations were just references to them.
"pretty shit that X is happening. Would be cool if there was this Y person to deal with that" -> "wouldn't it be cool if there was someone like Y but they were Z"
For stuff we see, you'd get something like a boy and a girl in a rural town where they were the only kids. Everyone, including them, assumes they'll get married but the boy is starting to goof off and daydream of leaving to meet beautiful women in the city while the girl is getting more and more frustrated trying to snap him back to reality. People read this, become writers/mangaka, and make stories referencing this or something similar. Then new ones come and reference the references. Eventually we end up with a few of the variations of tsundere and none of their behaviors make sense anymore.
Then we got this on fastforward with narou-kei or narou-ou type stories (what we often mistake for isekai). Start off with proper tensei stories where the mc was either old and experience or had a really fucked up life and genuinely needed to just...die and start over. Now, every 15 year old with nothing going on in their life is dying and getting 'reincarnated' with the exact same age and appearance and no family or background in the world to speak of.
TL;DR
Initially in a medium or a sub culture of a medium, you would get some real world idea or experience trying to be conveyed in the story but eventually many of the stories will just be about having shared experiences with the media or sub culture itself rather than saying anything about the real world.