So Komachi isn't weird with Seo, just Akira. And also everyone else.
I assume when Komachi says she loved the old Seo she means how willful and individualistic she was. It's what she told Satsuki she admires about her too. Komachi might idolize anyone willing to break away from social rules and follow through with their desires, good or bad. Too early to guess what that says about Komachi, but it probably isn't what Seo wants to hear right now.
Alright so, is it just me or did the President's moral suffered retcons? Because he went from "Some people deserves to die" to "Everyone will die you shouldn't interfere" to "Some people deserves to die" again?
Because like, why on his view Satsuki deserves to live but their Teacher doesn't? What is the reason that makes someone worthy of life in his eyes? He doesn't know almost anything about the people he is judging
Above board, Kai theorizes changing fated corpses results in another death happening later. He wants to make as little changes as possible but would save someone's life if they were valuable enough. During Sensei's arc he did say he'd be happy to save him. Satsuki is too valuable to let die regardless, since she can also see deaths, but he does consider her a good person too.
The contradiction here is his methods of murder have all involved probability and generating countless corpses for each kill, sometimes even getting bystanders' corpses to show up, but obviously that doesn't bother him.
In truth, I think he's desperately searching for justification. Ever since killing his teacher he's wanted to believe he's doing the right thing. He doubles down on this idea that some people are just so rotten death is all they deserve. And so this belief that fate demands death (which he has no proof of) reinforces the idea that his kills are simply the best outcome.
Satsuki is especially important because she's a moral paragon with the same powers. If he could get her to compromise her morals and admit his way is right, that would be incredibly reassuring. They wouldn't be murderers, just death's cleanup crew simply doing what's necessary. The pleasure he takes in killing is more like a fervent denial that he's doing anything wrong, since he can't take any of it back. He'd be a lot like Satsuki in that regard, traumatized and driven in an attempt to make amends for an early encounter with death.
Personally I'm not going to take this theory that each life saved results in another death as fact yet. There's just not enough evidence besides the incredible rate of deaths. If we're meant to tie this into the massacre in the first pages of chapter 1, why hasn't there been another mass death event like that? It's always one or two bodies. Clearly there isn't some death backlog that gets paid back all at once. So that must be something beyond this rationalizing of fate. It just seems to be important that Satsuki gets the trolley problem in her head for now.