You can't say "it's not needed for story" when you can't possibly know what's the story Mr Jet wants to tell. I'm guessing this game was never about a guy making (and fucking) his way to the stardome but about a guy trying to just choose his life's path. From that perspective it's obvious to me she needs to be the victim because she's the only real link between MC and his family, the only one who take family relationships in a caring way, as families are supposed to be. The good/well writing question should be if taking her out of scene this way feels realistic enough, or if the incident is well or bad scripted.