Hmmm. I can’t decide whether I agree or disagree with this comment. I mean, Sangwoo didn’t love Bum. People can be in a relationship and not love each other at all because they’re not into members of the same gender. If Sangwoo didn’t see Bum in a romantic way, then he’s not bisexual and is still straight. Sangwoo himself confirmed it. He never had romantic feelings towards Bum. He is most likely straight. (づ ̄ ³ ̄)づ
Have a good day
I never said that Sangwoo became romantically involved with Bum, because for Sangwoo's nature it is impossible. I wanted to address the fact that he thinks he's not gay, when honestly he never even had time to think about it. Maybe he is not gay, but he is not heterosexual either. Being a psychopath does not prevent you from knowing how to differentiate your sexual orientation, since psychopathy is a character flaw and not a mental illness according to experts. That is why I say that he did not have time to ration his sexual orientation or simply have problems with it. I researched and talked about it with people who study psychology and psychiatry and they all said the same thing. It was very irresponsible for the author to address this issue and answer a question about Sangwoo's sexual orientation without having "researched" more seriously about it! For you too, have a nice day ♡
Sangwoo was heterosexual. He was clearly straight. He never love Bum at all and had little to no romantic attachment to him. He dressed him in women's clothes and even had sex with him but he didn't do it because he was gay. He did it because he had serious issues with his mental health. Men do sometimes victimize other men sexually and still identify as straight. Jail for instance.
I will try to be as soon as possible, again. Sangwoo is a psychopath, a serial killer. He is not a mental patient, what he has is a character flaw! That is, with trauma or without trauma he was already a potential killer, his mother was just a trigger. BUT THE QUESTION IS THAT, because of Sangwoo's mother, better because of the life that Sangwoo lived at home, he ended up not having much time to think about him, he didn't have time to be a normal teenager and think about all these questions, which he only starts to think about, when Bum appears! (I'm not talking in a romantic way) BUT when Bum appears, Sangwoo begins to receive "love" and this is where his idealizations around Bum begin. Remember that Sangwoo's mother always hurt him, she tried to kill him little! That's why he was even more upset when Bum cut his wrists. AT LAST, from there you can already draw your conclusions.
PS1: Remembering that Bum is always willing to accept Sangwoo's crazy, so Sangwoo feels comfortable next to Bum. He says he's not gay for him, but the dick is tough! For me he came out bisexual at that time.
Just to wrap up, I wanted to say that I like Killing Stalking! It was a story that I couldn't stop reading, even though the topic is very heavy. But as a reading that comes to these subjects it is clear that I observed all these details and that honestly, for me they are serious. Starting with the approach of psychopathy and then, sexual orientation.
I don't think it's useless, but the level of psychopathy that Sangwoo fits into is almost the same as the Joker!
Sangwoo is not a mental patient because of the obvious fact that he is not in a psychiatric institution. Psychopathy is not a character flaw. Under DSM-5 guidelines, it falls under the umbrella of cluster b, anti-social disorders. It is a psychiatric disorder that both a product of nature and nurture.
The original comment equates sexual pleasure/interaction(in this case, the consistent rape of Bum) with sexual preference/proclivity. At the very least, this is damaging for IRL male rape victims who have orgasms and also eradicates male sex workers. Sangwoo RAPES Bum in traditional meaning, in that these acts are part of a need to maintain complete control. His hatred towards his mother is also a part of this, as Bum and the other victims, become "stand - ins" for her as he still seeks to overpower/violate/destroy/ultimately erase her through these acts.

I still think that Sangwoo is bisexual, because as much as he made Bum the image of his mother, Sangwoo knows that Bum is a man and his dick goes up anyway. It is impossible for him to be just "heterosexual".
Some people may refute and say, it is because of Sangwoo's psychological disorder, but guys, do you really think that a potential "heterosexual" psychopath holds a "man" hostage and has relationships with him? At least I never heard of it. Not even Hannibal Lector was like that.