This is what I was about to bring up as well, although not so bluntly.
This kinda reminds me of the (Akane)Earth Dragon argument back in the Akane topic. Just because a character says something doesnt make it automatically true! I personally see those lines as Haruka realizing that Kanata was not “truly evil”, justifying that Haruka should rekindle her relationship with her now, even though she hated her before.
@Naoki_Saten said something about "no one would read those lines and assume that the message was that nothing is truly evil. Haruka, too, was probably not actually thinking this literally. That was a very emotional moment for her. All she was thinking about was Kanata. Thinking of her family in this situation would have hampered her progress with Kanata. Or perhaps she was being optimistic in this moment of happiness, considering that it might be possible the rest of her family, like Kanata, wasnt all bad after all.
I will also point out that these lines are a way of showing how both Haruka and Kanata’s characters changed. Haruka believed that because Kanata had done bad things to her, Kanata must but “truly evil”. Kanata believed (dont remember the lines exactly, but it was more toward the middle of the route) that when someone was happy, someone else had to be sad. Both of them were proven wrong when they stopped hating each other.
Now, even if all that I said was true, do I think that writing it that way was really the best choice (seeing as it obviously caused this whole current argument)? Ehhhhhh:
There is another possibility that I wanted to bring up, though Im not sure how likely it actually is, so I put it at the bottom. (Refrain) The entire world was created so that the people in it, such as Haruka, could fulfill their regrets, yeah? Wellllllllll, the only thing we hear about Haruka’s family comes from Haruka. So I guess what Im thinking is, is it possible that we dont get the whole story, because the world doesnt always follow reality? It changes to be optimal for ridding them of their regrets, so maybe the optimal situation was that none of the characters we hear from know the reason why the Saigusas/Futakis acted the way they did? I dont know, seems kinda unlikely, and yet, I think its completely possible.