That's not really what I'm arguing against. I'm saying that if Kyousuke wasn't a siscon, nothing would have ever happened. Because Kirino showed him less love than to a cockroach from the beginning. A normal brother would have set ever more distance to such a sister. Kirino is obviously a brocon with the worst personality in the history of anime, but if Kyousuke hadn't been a siscon, this would have been a really short story. Only by being a creepy siscon, he can stomach all the torture and insults from Kirino.