To go back to the previous chapters, there was a part where should a bullying happen with Daidouji, the whole class would've noticed Yukishiro doing sorts of nasty endeavors already, let alone blatant physicality and/or verbal harassment. To think that the class would agree upon the: "We're sorry for not defending you" that quick is, to me, grating. Like, yes, there's skepticism already whether or not Yukishiro would even do such deplorable acts, I know that, but the thing is, none of them stood up for her before, not even a "Does anyone have a palpable proof or are there any witnesses whatsoever that we can examine whether or not the message passed on is legitimate and absolute?" Heck, the teacher is also unprofessional. IIRC, she's (probably) a rookie teacher, which goes to say that she's inexperienced, I understand that. But you're taking a role of a "guide", which goes to say that this job is to not only teach, but also supervise any class concerns, incidents or adversities, yet she almost drove out one of her students with her pillar of evidence only relying on one-two letters with Yukishiro's name on it. Not the slightest bit of doubt. I cannot also say in full confidence whatsoever the school policies are in regards to student disputes, but the teacher could've at least acted professionally and not blindly side with a "definite proof" she has on hand without actually consulting to the bullied student herself.
By the way, wouldn't this event orchestrated by Hanabi originally backfire on her? I mean, she wants to "swat off the flies surrounding her senpai", so to say that this resolution would deepen the relationship between Yukishiro and Ichinose? Massive loss for her again XD