Incest themes in novels, manga, and anime were toned down starting in 2011 after a law about it was passed, leading to outright cancellations of some series like
Rika.
What we see today is tamer than over 15 years ago. Lot of stepbrooooo situations and innuendo.
Good point - by eliminating disturbing series where the incest (abuse) is the focus of the work and allowing unrealistic Comedy Incest to proliferate, they've definitely normalized the latter. To the point where now I feel like having a harem rom-com where the sister isn't a target requires some kind of excuse or explanation. It's shallower but broader.
I can kinda see why it would drive somebody nuts if they're triggered by incest, even if it does nothing for me either way.
Also Jesus H. Yikes to Rika based solely on the series description.
Edit to add:
WP on the above-referenced law and the some of the moral panic surrounding it, which is really interesting in a lot of ways. And I tried reading the first chapter of Rika and think that it would take a very curious and open-minded person to endure its content and implications, unless they're
into incest or younger middle-schoolers.
I think that work is going for a partially "oh gross" reaction to connect us to a shamed and conflicted protagonist, but the "gross" is the only thing that connected for me and all I could think was "dude you need to have a real convo with her I'm so worried about that girl" while he was
goonin' away to his imouto. I totally get why a publisher serializing that work in that political and media environment would beat it to death with an axe.
Revising my evaluation upwards to Jesus H. Yikes on Bikes.