Ok, you right, there's minor or subroute with each possible character but, and this is major point here, they all just a pieces of major 2 routs. So if you don't want to Sofia have anything with Aiden, for example, you can just get rid of him (not now of course) so you block scenes with him in Filth route.
Or, in other words, there's 2 storys and you can decide: 1) what story do you want to see and 2) what parts of the chosen story do you want to see. And if you don't want to see scenes with some of characters you can just get rid of them, one way o another, so you block these scenes.
That's exactly what I'm tolking about. So why not give the player the opportunity to choose not only the characters with whom Sofia will hang out, but also for a couple of them, how she will behave with them?
Yes, and some people thinks that incest or cheating is gross so they, for exaple, don't play games with incest content. In the case of this game player have limited options to choose what he want get further, but dev can't please everyone.