I think sanho probably had something going on, the story says he would have short outbursts but then be nice to him immediately, which isn't good either but i think it wasn't out of intent to bully but more so i think that he was angry with mc being so compliant and weak, with reference to another panel of sanho talking about why they should be laughing at his wounds and in the i believe first chapter about him saying similar thing directly to mc. It's bad that he was still kinda mean to mc, but since he also was the only one actively reaching out and kinda talking to mc, i feel neutral about him.
And also i think the ml was pretty much a bystander, one of the earlier panel shows sanho talking about how he shouldn't be involved and jeeho says he isn't, also the fact that jeeho doesn't quite know mc and vice versa by the end, makes me believe that he never bullied him or even interacted. Jeeho was sticking around the bully for the bike i believe and being a bystander to that.
This isn't quite defending them, i think in a way, they all turned their life around by the end in a tragic way.

Hmm guys anyone can give me summary on this and am I the only one who didn't liked sanho cus he obviously bullied mc even if they were few punches and also the ml being involved with bullying!? I'm so sry to say this but those two are definitely not that innocent even if mc were in love with them it's still wrong yknow!? It's sad and bittersweet but still wrong yknow, I was just here for the victim dip-sheet Kim (sry can't remember his name) i don't really expecting anyone coming at me defending those shits cus if that happened in real life the result would be lotta different