>>714051451Because it's not about learning the true meaning of family or some gay shit like that, it's about incest ecchi purity.
It's like... how do I explain this to some weirdo freak who isn't into mother-son erotica? Imagine hearing that your favorite band is coming to town and you get tickets for the concert, but it turns out to be a tribute band. Or you go to a museum to see artifacts and fossils, but everything on display is just a reproduction. Or you check out an anime series purporting to be about a young man getting into sexy hijinks with his smoking-hot biological mother, but it turns out they're not actually blood-related. It's like that.