...we've had modern love hotel themed dungeons complete with sex toys this whole time but it's the onigiri that makes you draw the line?
the love hotel stuff is setup like a weird, almost alien thing that they don't really understand and the point is that it is incongruous with the rest of the world. I dislike that onigiri and very explicitly idol nonsense are included like the most normal thing in the world in a "of course they have this" sense.
Also maybe because idol culture crap and rice-fetishizing are easily two of the biggest repeat offenders in the category of "inexplicable Japanese-ness in the middle of a pseudo-European high fantasy setting" inclusions in fantasy/isekai manga as a whole so I'm just sorta tired of it.
Also also I just particularly hate idol culture so I'm happy to get away from it and sigh when it ends up showing up for no good reason.