Because it has a harem route. In heroine individual routes the MC fucks single girl per route (the moment he choses side heroine it switches to her specific route) and develops "romantic" relationship with them, in the harem route he does that with the whole family.don't know why this has harem tag unless you can avoid sharing that is(which I doubt you can)(this site and it terrible use of tags plus not having more tags plus just cramming multiple things in one tag)
theres still a high possibility since its a j-game and the genitals and muff looks typical for decensoring.