The issue isn't that, the issue is literally the words Suzuki said right before it happened to Sugiki, the Manga is still good and they ended up together so who cares, but it doesn't mean what he did isn't shitty and doesn't make sense as to why he would do it to begin with.
The movie might not be as good as the manga but at least it removed a lot of the problematic stuff this Manga had, including something that does count as cheating even if they were never together.
It's like you are going on a few dates with someone, you two aren't official but things are getting REALLY serious, then you discover your almost boyfriend slept with someone while going out with you.
It's still shitty and wrong, even if you two aren't officially dating.
People aren't overreacting, they are saying the truth/what's right, you shouldn't do this.
And I read that, I know it.
But right before that he EXPLICITLY said "I won't sleep with other guys" so even if not dating the relationship was serious enough to NOT be doing that, he promised and what do they show us next?
Him after having slept with another guy.
The fact that he made to promise to not sleep with other men means the relationship even if not dating was serious enough to NOT sleep around/he shouldn't be doing that.
It's not like I'm pulling that out of nowhere, it's literally written there, so by definition I should take the "I won't sleep with other guys" seriously given it's literally a promise he made, not just a white lie.

I don't feel anything about Suzuki and norman. Y'all are children