@Leonhart93
Obviously I can't make myself understood. It's probably because English isn't my first language.
I can't give you a better analogy because there are no better ones. He blackmailed her and his behavior caused her letter to be read by everyone, and that was it.
So:
1. Eunjae put a direct letter to Gunwook in the RIGHT locker, then decided to take it back. Meanwhile, the club's people arrived and she hid in Moonyoung's locker.
2. Moonyoung waited for everyone to leave, then let her out and steal the letter from her hands to read it (cap. 9) and already here we are on the crime. She didn’t put it in his locker or give him the letter. He took it from her hands, opened it, and read it in the face of the privacy law.
3. He started using the letter to harass her. Despite Eunjae’s repeated request for the letter to be returned to her, he did not do so and used it as a pretext to force her to go out with him (in real life, such behaviour as well as a crime would also be creepy). Sure, then Moonyoung said he’d keep it a secret. But why would Eunjae believe him? What has the ML ever done to earn MC’s trust? Nothing. Absolutely nothing.
4. The day he left for the training camp, with the house full of strangers, he looked for the letter in the drawer and then left it in plain sight on the bedside table (cap. 30). With the house full of people. A pink letter with little hearts on it, typically from a love confession. He could have written "read me and make me known to the world" on it, since the effect of such a letter on the gossipy and nosy soul of a bunch of teenagers is the same. Who took the letter? We don't know. It doesn't even matter at this juncture, the fact is that Moonyoung allowed it to happen by behaving stupidly and leaving something unattended that didn't belong to him and that he knew very well could harm the owner if it became public knowledge.
As already mentioned, if you have data of a third person and these data are stolen from you, the culprit is still you because you have not adequately protected the data. Theft is another crime and is followed by another legislative process, but for data security it is you who owns it.
5. He left Eunjae to unravel with an entire class who boycotted her and cornered her. Of course, it is little compared to the serious problems of the world, maybe it is not worth bothering justice for this reason (actually no, there are those who have sued and won the case for much less in this world? jail? Of course not, it's a civil offense. Fines like there's no tomorrow...) but it's a small thing for us. For me, grown woman.
For a 15-year-old girl with only two friends in the world, knowing that she betrayed the first and that the second betrayed her is worse than the war in the Middle East or the pandemic flu.
I mean, come on. Even Moonyoung says he feels guilty for not keeping the letter carefully (Cap. 26) and that he behaved like an assh*le by keeping the letter which was not intended for him. I don't understand why you want to keep defending him when the character himself knows he's done something wrong. He apologized... so what?
Apologies, especially for events that have led to trauma for the victim, are only for those who do them, to wash their conscience. Those who receive them do very little with them, since the trauma had to be dealt with by now. What should Eunjae do now?
“Ah, for the last ten years I’ve felt like sh*t, but I finally managed to put my life back together and good or bad, I’m happy with my family and my job. Not serene because I still have a teenage trauma trail, but happy.
But you’re back in front of me. You, who for ten years I’ve considered to be the cause of my pain.
And now just because you apologized I should cancel ten years of my life and pretend that everything is as it was before and that we are friends again, and in your hopes also lovers?
Yeah, sure, that's how it works. 😐"
(Unfortunately, the great love will triumph and blablablabla, like bullsh*t. Because it’s only in stories that first love triumphs... in real life I don’t remember the face of my first love. In real love life, the only thing that really matters is the last. )