Well, in the pilot when Sisko meets O'Brien and then goes to meet Kira O'Brien stops him and asks if he's ever worked with Bajoran women before, which to me indicated that he was commenting on her attitude and behavior. However, I don't think she was a bitch at all, and I think it was weird that O'Brien was stereotyping Bajoran women specifically instead of Bajorans as a whole. Usually Star Trek conveys a high level of species-stereotypes and a lower level of gender-stereotypes, but not in this case. Whatever.
I always thought O'Brien said that after the Enterprise had some fun with pleasant and super-friendly Ro Laren. Not as much as stereotyping, as speaking from his personal experience.