(Spoiler warning, and in fact this is probably going to be incomprehensible if you haven't seen the episode or read a summary, such as here.)

I suspect that we're supposed to consider Nami an unsympathetic and weak character and feel that her sisters were more or less in the right. I have the opposite reaction: this was a major parenting failure and Nami is a victim. Here's why:

If someone is traumatized so badly that they have horrifying hallucinations, the correct response is not to tell them to stop whining and get on with their life, it is to get them into therapy, now. That the cause of the trauma was something small and petty makes no difference, except that it probably means that you have two problems.

But what if what Nami experienced wasn't a hallucination but real (or at least, not just inside her head)? Then there's still a major parenting failure, this time of security, because it means that Aleida was able to get a lot of information on Nami's situation and state of mind, then penetrate the family estate's security to exploit it and take advantage of a vulnerable person who'd been deliberately kept ignorant about what was going on.

(It seems clear that there is a significant security failure even if Nami is hallucinating, since Aleida knew just how and when to exploit things.)

So my sympathies are with Nami, although I suspect that Sunrise disagrees with me.