Oh good, let's talk about this episode, cause I find it really disturbing and confusing! Only because I'm not actually sure what message the show is trying to send with that last line.
My take on the episode, and the character of Kira in general, is that she truly believes what she did in the resistance was right, but she's aware that it's an opinion that not everyone shares. She knows she should
feel bad, and should claim to feel bad, but in her heart she doesn't really.
I liken it to Dukat when he goes off in "Waltz" about how much he hated the Bajorans. He's gone insane and lost all his filters, so he says exactly what he thinks. I think Kira, about to be killed, has no reason to make her opinions palatable in the way she does when she talks about her past deeds to more upstanding citizens like the Starfleet people, Kai Opaka, or Odo.
I think she also gets her buttons pushed really easily by people calling her out on the things she's done (think Marritza in "Duet," whenever Winn makes some remark about her being violent, and what Prin says to her here). She doesn't like being made to consider if she did the right thing. So I think that long monologue about how they all deserved to die is her trying to convince herself as well, or at least to shout down the doubts that he's placing in her mind.
Because really, he has a point. In my opinion at least, they are both victims, and they are both murderers, but he is somewhat less guilty, because he was more careful about who he killed.
The big dilemma I have with the ending is that I haven't the slightest clue what they were going for. Without that last line, I would say that Kira's face shows regret for how it ends, which I would read as her maybe realizing that he was, in a way, justified in his actions, and here's yet another dead Cardassian at her feet, which even though it was clearly self-defense, kind of reinforces his point.
But I have no idea what the last line means. Because they're both guilty and innocent in their own ways, it can be read either way. The one thing I don't
think it can mean is that they're both to blame -- one has to be the light and one the dark, there's no talk of twilight or semi-darkness -- so which is it? I find it hard to believe that she thinks he's the light. So that leaves her as the light. Which is messed. up.
This is why this episode disturbs me, even more than "In the Pale Moonlight." Sisko knows exactly what he did. If she comes out of this episode thinking she was 100% innocent and he was 100% guilty, that's way more disturbing to me.
edit: OR, is she saying that they're both guilty of the same thing: using their original innocence to justify future violence. That would be a perfectly valid lesson to take away from this story, but if that's what it's supposed to mean, it's really
Somebody please share some ideas, I've always been very dramaturgically confused by this episode, and would love to hear what others think!