I have nothing against her taking out a personal grudge, but claiming that it's because it's her "duty as a whatever the fuck her last name is" is just pure ignorance. Mindlessly doing things because you were told to has been proven time and time again to be fucking stupid. Even children are told why they're being reprimanded or scolded. Just say you're doing it because you think your sister has been framed and you're pissed, because that's clearly what's happening here dumbass.