I like Kuniharu as a character but not as a person
I think Kuniharu is funny because he's a pathetic loser, and I LOVE pathetic loser men. That's my thing! But genuinely, in real life he would be infuriating, and he's absolutely meant to read as a shitty parent.
He honestly reminds me of this guy:
He's so pathetic that you sort of feel sorry for him, and his shittiness comes from insecurity.
Kuniharu feels insecure because both his sons are more intelligent and/or powerful than him, and he expresses his resentment over this by projecting and constantly insisting that Kusuo is an asshole who looks down on him (which is kind of a self-fulfilling prophecy, since the way he acts due to his own insecurities only makes him seem more pathetic in Kusuo's eyes). He even talks about how much he wishes he could beat the shit out of Kusuo in front of his friends (I can't remember if that happened in the anime but it was in the manga) and when Kusuo turns small that time his first instinct is to kick him over to show that he's "the bigger man". The extreme jealousy he feels over his own sons is... really messed up, to be honest. He feels the need to be above someone because deep down, he feels inadequate.
This sort of person totally exists in real life. He's the manipulative husband who won't take accountability for things even as he apologises ("You stole my coffee jelly but then I smashed all the windows in the house, so we're BOTH to blame"). Like Toritsuka, the joke with Kuniharu is usually that he's a slappable guy who gets his ass kicked.
Obviously he has his good moments as well. There are times when he gives Kusuo genuinely good advice (like in the surprise party episode) but that's the thing! Even the most violently abusive person will have their good days, and someone who's just generally a bit shitty isn't going to be shitty all the time. He's a human being with lots of different sides to him!
This is a bit of a ramble, but I just see Kuniharu getting polarised quite a lot where people will either say he's an evil abusive asshole or they'll say he's perfectly fine, so I wanted to put in my two cents.
