A survivor/past victim (is he a victim at present? NO) who is perpetuating the cycle of abuse. He didn't help the kid who was being abused by the same abuser who ruined his childhood. Ironic that sunho/that kid was the one who saved minjae that time at the orphanage too which in turn brought the attention of the abuser onto Sunho.
He's also an adult now and has everything a regular person needs, he also lived his adulthood far removed from the trauma of his past. So what does he do- he refuses to help that one kid and metaphorically spits in his face after that schoolkid tried to commit suicide and was hospitalized. Unlike in the past, adult Minjae had the power to help him and thus break the cycle of abuse.The abuse which made him unstable as a kid and was partially responsible for Eunsung's murder/death. You see how this shit is all interconnected? The difference is his power and privilege and how he abused it too. He could have finally hold his abuser accountable but no one is even asking him to be the perfect knight in the shining armor either - he could have at least tried to move sunho from the situation/inform authorities who could have helped sunho instead.
I think the author tried to show the ugly side of abuse and never moving on for every character except Taehyun (I have mixed feelings about him because he forced himself on Minjae at school during their second workday when he was repeated told to stop - that was textbook sexual assault) who redeemed himself a teensy bit. Not all victims turn out to be empathetic, some might become sociopathic - minjae made himself numb to everyone else's pain unfortunately. The cycle of abuse and revenge won in the end. But bottom-line is that ofc Minjae is to be blamed and must be held accountable because he is an adult now who also got a shot at life.
Minjae,Hyukjoon,Taehyun and Eunsung they were all victims.
I dont hate Minjae or Hyukjoon they didnt asked for what happend to them , they didnt do the things they did cause they wanted to. Yes Minjae is a piece of shit for killing an inccont child but he was used and abused and thats what drove him im not justifying his actions but what im saying is He is also a victim.