I know that there's some controversy about Kira's claim in that scene that there were no innocent Cardassians on Bajor, because episodes like Duet had given her a new perspective on such issues, but I completely buy that in that moment she believed what she said. Some part of Kira does believe that, she couldn't have lived through the occupation without some of those dark thoughts, but in normal circumstances her ability to reason will overrule such thinking. But now she's pregnant, her back hurts, people have been treating her as a delicate specimen for months, and some crazy guy has been murdering her oldest friends. So yeah, I can buy that she doesn't have time for reason or feel-good peacenik sentiments in that moment, she just wants to hurt and kill the guy that has her trapped in a chair.
I agree. People are complex and multi-faceted, and good characters are therefore complex and multi-faceted as well. I think we all agree that Kira Nerys is a good character.
In my opinion, personal growth rarely involves cutting anything loose completely, because that's not growth, merely change, and people can't let go of themselves quite that easily. Indeed, I'm not sure it would be healthy. Kira hasn't become a new person over the course of her time on DS9; instead she's grown and become ever more complex. Her outlook on Cardassia, the occupation, her own role in fighting it; these have changed; that doesn't mean she's incapable of accessing her former, more cleanly black-and-white perspectives, merely that she's learnt enough to be wary of them and keep them from dominating her outlook, at least most of the time. But when she's under the stress she is here, she can revert, and that doesn't contradict or invalidate episodes like Duet
. It just shows that for all Kira is in the present, she, like anyone else, is partly defined by her past. She learned as a youth to keep things simple and clear-cut, as a means of surviving and achieving the goals of the Resistance. Just because she often seeks to put aside those lessons and turn the direction of her life around now that she has the chance (her scene with Opaka in season one being a great example), it doesn't mean she's "unlearnt" them. And it doesn't mean that when she's had a very bad day due to someone who hasn't been at all
succssesful in escaping the ghosts of the occupation that she'll necessarily have the patience to reason and reflect.