Again, I really don't care about what happened, I care about the intentionality. Kirin is a teen with multiple layers of cope hiding her insecurities and makes bad choices because she wants to pretend like she doesn't care about anything. She doesn't actually understand the consequences of her actions because she's a dumb 14 year old. And while it's not good to be stupid, it's a lot more forgivable than fully understanding what will happen and doing them anyways.
On Nodoka, Yumi was already changing before she did her shit, but her feelings towards Sensei weren't changing. Again, in the route where Yumi just walks out, there was no revenge taken besides inconveniencing Yumi, and she doesn't try anything afterwards. It's clear that revenge wasn't the sole purpose, otherwise Nodoka could have made it a lot worse. And sorry, but I don't think Nodoka feels an ounce of empathy for Yumi, so it begs the question why Nodoka didn't make things a lot worse if her only purpose was "revenge."
Also, I wouldn't use Futaba as a judgement for Nodoka's character when Futaba can't even understand Nodoka during the book scene. And I don't really get why you think Nodoka did anything wrong there. What did Nodoka actually say that was incorrect? What, that Nodoka should stop doing what she believed as extremely important so Futaba could feel better?
Nodoka isn't evil. There's a quote from somewhere in the game where Sensei describes him and her as two kings sitting on their thrones, and it's a pretty apt description to Nodoka's role. The world is built for Sensei to develop his harem, but the story of the world is being told by Nodoka. And while Nodoka certainly does care about her friends, her greatest priority is telling this story.
