I feel like Haruji just being a straight up evil asshole is a bit of a cop-out. Until now it seemed like he was genuinely struggling with Taiga's death, too.
I think people are looking at this a bit wrong. I can understand why you think "oh its a cop out," but he's been a dick the whole time for sure. It's always been there. But a lot of people saw him, and hoped for better. They thought he was grieving. They thought he wasn't irredeemable. They thought "hey, this guy's going through a rough patch too."
You were Mio. You were their friends. You're every friend of an asshole, every battered spouse, every abused child. "There's gotta be more to them," you say. "They're people, they're complicated, but there's good in there," you say. "They're just lashing out," you say. You see a future where they're better, a potential world where they're happier, where they don't act like this. Maybe, if you're his boss, you give him some slack. If you're his friend, you try and get him to talk about it. If you're family, you try and tiptoe around him and keep away from things that make him upset. You're rebuffed each time, like they were here, but you still dream of a time where they're able to finally talk it out. Finally feel better about it. Finally be more than an awful dick who only cares about themselves, because they expose their pain and let themselves be better.
So you built that scenario up. That he's going to find Mio, that they're going to talk it out. That he's going to reveal more about his pain. That he'll apologize for being so distant. That he'll come to terms with the idea that they're both sad for the same reason. That maybe... maybe they can figure this whole thing out together.
What'd you get? Well, Haruji. A violent, entitled asshole who centers everything around him and how his life has been interrupted. A pathetic man who can't take responsibility for anything, not even his lack of desire to have a child. Who lacks the power and resolve to actually do what he wants, so just blames everyone else that he can't. He didn't wanna be with Mio, he didn't wanna be a father, he didn't want to have to be 'the man who lost his son,' he didn't want any of this, and it's all Mio's fault. Him having a son, that son dying, his loss of status, his inconvenience... all hers.
In this moment, Haruji was revealed to you. Just as he was to Mio, just as he was to Dobura. None of you liked what you saw. But that's not a flaw in the story. That's what people like this are
like. They trick you into thinking there's something
more to them. Somewhere, under all that, is a good person. But there
isn't. Their hostility comes from resentment. Their resentment comes from victimization. Their victimization comes from entitlement. There's layers. There's a complicated stew of expectations and powerlessness and the angst that comes from a self-image that doesn't match with reality.
BUT IT ALL SUCKS.