the more I think about it the more I believe that why waves hands The Modern Isekai Tropes (as exemplified most recently in the dialogue that appears in Forspoken) bother me so much is that they seem to signal a sort of irreverent carelessness of the work's own setting &/or lore.
Like, if the main character, meant to be some sort of newcomer to this place, sees no issue with mocking/goofing on the traditions of the world that they are a newcomer to, why the fuck should I, the audience, care about the world? I feel like I am being told "this does not matter, don't worry about it"