I mean, isn't a lot of the stuff Kyou did because she intentionally stole him away in the first place because she knew Kyou liked him? Like, from his perspective he's just fighting for the person he loves against someone who is only dating them to hurt Kyou. Like, that's kinda the whole premise, she hates Kyou, and wants him to suffer, so she dated Rikimaru just to fuck with him. With that in mind, yeah, pretty much everything Kyou did is fair game imo. She was always the antagonist, this is how story reveals work.