WTF are you talking about? The curse makes victim horny (read title of game), it doesn't make them good at corrupting others. You realize that the sister doesn't actually corrupt the villagers, everyone was already a pervert there before the curse.
I don't know about that, as you say it makes Yuuki horny and take away her judgment, but we have to remember that the villagers was pervs when the demon aura was affecting them before the cures and they where not pervers to her before it arrived, the dialog changes if you talk with the villagers after the demon leaves. And go back to pervs when the curse kicks in.
I see it more as Yuuki being receptive to sexy stuff and makes people around her do things they desire to do to her.
And it escalates to more pervasive fantasy as she gets more and more corrupt. I wouldn't be chock if she leaves that the villages would wake up and be embarrassed of what the have done.
