Well, a lot of people are never going to like Ibusuki. Ibusuki was legitimately being a bitch during the first stretch of the series. A lot of people posting comments about stuff like this seem to hang onto that kind of first impression as a series develops. I'd also agree that frankly, she's still a pain in the ass despite being less bitchy. She still pretends to be a boy, but also still gets irritated when treated like one by Tarou and other things like that, at which point she generally aims that irritability at him like a weapon. Which is arguably still pretty bitchy, no? Taking things out on someone who's only real fault in the situation is believing your lies.