Absolutely right. It seems that Nanjo's flaws of being naive, rigid and having tunnel vision make some of the readers think it's a reason to say he is as guilty/bad as the other 2, and that's a very weird reaction. And I say this as someone who doesn't dislike any of the main characters.
Nanjo gritting his teeth for the sake of the deal is not proof of love for Mokyeon. Nanjo's body reacting positively to sex is not proof of love for Mokyeon. Nanjo warming up a bit and going along with Mokyeon and watching a movie/dining together is not proof of love for Mokyeon. That's just a dude making the best of the weird situation he's in.
I don't know how are people surprised by Nanjo's reaction in chap 33. Were they as delusional as Mokyeon ? Nanjo was delusional too with how he viewed Sunhwa and how he thought they were in an exclusive relationship (+Mokyeon hovering around), and in the later end of season 1 he seemed to slowly distance himself with Sunwha (faking being sick to not meet up for example), but does that mean that he HAS to go running into Mokyeon's "loving" arms now that Sunwha doesn't want to have anything to do with him? Hell no ! Especially given Mokyeon's role in this fuckfest lol. One cna only take so much.
Anyway I'm interested to see where things are going
Yes, totally. Everyone took mokeyon side because the story is from his pov so he puts rose tinted filter over it but anyone can see he is no saint. Sincerely i do feel more empathy towards nanjoo because he is a victim being manipulated by both the other two, who are horrible people. I do hope for justice for him.
His part on the story feels like to be a puppet by horrible people while the audience cheers his abuser because he is sad now.

People forget nanjo was blackmailed and coerced ( raped too ) into this relationship and believed he was doing all that for the sake of " protecting " Sunhwa.
He was so in love with Sunhwa he let Mokyeon have his way with him just to protect the twink ...
Even if he enjoyed the sex, does enjoyment turn to love like that? Mokyeon feel in love because Nanjoo is very kind and selfless.
But in Nanjoo eyes, he is now someone who not only took advantage of him, who he began to feel some sorta of friendship and now has betrayed him and broke the trust they had and broke his relationship to the twink he loved.
Nanjoo doesn't need to reciprocate his Mokyeon feelings just becase Mokyeon is sad that his actions had consequences. He deserves the punch and more.
The name of this story fits the plot, boundary of delusion, Mokyeon is quite delusional right now ...