I'd like to think that, but Kirin already thinks he raped Molly (which turns her on), and after finding out Sensei and Karin were together before she came home bawling, one of the first things she does is question why he didn't call her to suck his dick:
She actually seemed mad at Karin and ended up chasing her down to find out what they did, at the end of the event.
Then Kirin was getting off at Nodoka's meet&fuck later.
Keep in mind that the main reason Kirin hasn't tried to get Sensei to assault Karin, is because she doesn't want her sister getting fucked more than her, as she points out in her Chapter 2 'Made Out Of Nothing' Event. Karin is like Ayane to Kirin.
Although, maybe Kirin's had a change of heart...She was trying to be better lately.
Edit: I do think Kirin cares about Karin, though. She also cared about Ayane and actually gets mad if Sensei is cruel to Ayane. It doesn't really amount to much. Even Miku, the person Kirin wants to protect the most, is someone she'd let be taken advantage of.