I agree. She also needs counseling.
Protecting your oppressor is a clear symptom of Stockholm syndrome.
Of course she's naive because she's clearly a kid who's grown accustomed to her situation and having outsiders interfere with her situation in a weird sense is like disrespecting her territory. Like she in her mind is basically an expert at dealing with her abusive father and having someone intervene with a method she's never used before is insulting to her in away. (especially if she also has to be mindful of Siyun's aggressive nature as well)
She doean't know what a healthy household looks like nor has any professional on the outside confirmed that Siyun's response was actually reasonable. That's what I like about this story because it thoroughly depicts the very real case reports of this exact type of scenario of miscommunications as well as thought processes of how a real world case would play out as well as the resulted actions (sometimes injuries and sometimes murder).
All-in-all neither Siyun or Jeongmin are wrong in how they are responding to each others situations it really is just that they ARE just kids and don't think anything thoroughly enough because their minds have yet to reach that type of worldly maturity.
The power dynamics keep teetering back and forth like a see-saw.
Does Siyun have a lot to work on? F*ck yeah
HOWEVER, Jeongmin is hella naive and is steering him down the pathway to his own destruction (she should have hooked that man up with therapy from the beginning, not telling him to go meet his estranged parents). I got beef with anyone who believes the "you should forgive them because they're your parents" crap. His parents are clearly horrible, even with her never meeting them, the fact that they gave up on him so fast after finding out he got injured is insane. Her encouraging him to pursue that relationship is messed up.
Also, I'm confused about her overreaction to him grabbing the father. If he had used excessive force, I would have understood, but they were in a position where both of them could have been injured. The father has a history of violence, he had Jeongmin by the hair and he's twice the size of Siyun, what he did is arguably reasonable and would have been a pretty common reaction (it probably would fall under self-defence too). Her claims that his reaction to wanting to protect his loved one (an act made from the need to protect/concern), is on par with his malicious actions prior (acts made from a place of anger/malice) is completely unreasonable. I understand not wanting to be with someone violent and wanting him to grow and develop as a person but if you are going to freak at him in a situation where he was clearly scared and feared for your safety, maybe you should just break up (those conversations should be said calmly and using non-blaming sentences and redirection). But honestly, if she is going to continue to get upset at him about everything and set these weird conditions regardless of how they are working out (I'm still petty about the parents), she should just call it quits because clearly, he's not what she wants.