I agree the concept is not new, but I don't really understand your logic by thinking the author don't do world building. Of course there is a world-building, despite it not necessarily being a new concept.
To me, it is like saying "you don't cook that cake because you are just following an already available recipe on the internet". Of course I cook that cake myself, I just don't invented the recipe.
For the uniqueness, I think
The Negative Effects Of Women's Education chapter is quite unique in a sense that the girls are delusional because they are being taught. It is clear the author put some thought in this. I just think it is not fair as I think you are dissing the author for "not putting thought" in this series when it is clearly not the case. Using an already available concept is not necessarily "not doing world-building".
With your cake example it's like someone praising the cake you cooked as an amazing new recipe, when you just followed an online recipe and swapped vanilla extract for strawberry.
Cooking the cake would be the writing of the story, which author fully did himself while following the recipe.
Like yeah, this is
technically world building even if he came up with almost none of it himself. Every long eared elf is technically a new fantasy race even if they're all copying Tolkien.
And your chapter example is unfortunately not unique... It is actually the most common exposition for this genre when the story switches to a girl's POV. Explanation of expectations of what 'typical' men would do, why girls are sad about it, in order to directly contrast what MC does, and why the heroines love him for it. I also personally dislike it when stories use that exposition because it feels like they're jerking off the MC, giving a lecture of why he's so great instead of just showing through action.
The most different thing about this particular story is that there are 3 guards instead of the typical 1, a secondary male character that is
slightly more developed than most other stories (not all, some have male characters that are actual characters) and his obsession with Yuri (usually they would have an obsession with yaoi), and the lack of actual sex (not all that unique either but considering this genre started in porn, the lack of it makes it rarer comparatively due to the sheer volume of smut using this genre)
I'm not dissing the author for his work, he does execute it well enough, but the author didn't come up with a new recipe, he's following the existing recipe by the book.