I get that. Sanada was the one responsible for things taking a turn for the worse. However, I think the reason why I personally like him is because he not only admits his culpability in all of it (he was right about Kanezaki too btw) but he also strives to be better. He's gone beyond just treating Itonaga with minimal decency or punishing himself for his early behavior. And that's so refreshing.
Imagine the guy that was a bully now regrets all his wrong doings and trying to change but then their friends who also joined in to bully suddenly said "but it's your fault, we just joined because of you", they're part of the act too y'know, getting mad at the person who's trying to change feels like they enjoyed the bullying more. This is the problem with bullying, there's literally kids who probably be the side characters who laughed at the sides and probably joined in too and do more damage than the person they called out who started it first.
Thank you hunterx2 for your honest comment. I agree with you wholeheartedly.
I just feel like, no matter how I spin it, Itonaga got the short end of the deal. Even when he was telling the other bully off, I couldn't help but think "Well, they are right". Itonaga was only billied to the extent that he was because of Sanada. Itonaga had friends and was enjoying his life. Some people made fun of his eyes but he was still doing fine. Then Sanada makes his life so bad that he has to transfer schools in the middle of the year.
The characters are both charming but it just feels like they made the whole thing about Sanada getting over his guilt for being a bully and not Itonaga being bullied. And their relationship, while cute, feels unearned.