I'm so confused. Why not just tell him you like him? Why turn it into a threat or a transaction? Given that Wolves Behind Bars also had a very rough start to the point that I even stopped reading it for a long time, cuz I thought "how the hell is this going to turn it a love story?", but then it turned out to be really lovely, one of the sweetest BL I've read. So I will trust in the author and continue.
I'm still hoping that this will remain a retribution and not a redemption arc.
Let's be real, could Siwoo ever show his face to Suha if he actually got into a relationship with Dohyeok? And it's not like there's anything between them besides sex. Dohyeok clearly doesn't know a thing about Siwoo and looks down on him as he does everyone else.
I agree with lot that you've said, but the whole point of a relationship is getting to know the person of course Dohyeok doesn't know anything about Siwoo, it wouldn't Make sense if he does at this point. The author is giving us foundation st this point "enemies to lover's" redemption..it's very obvious Dohyeok is gonna go through something similar as Suha and he's gonna apologize and we will have to see if Suha forgives him or not.
My best guess is that he's displacing his anger at the grandfather onto the mc. I don't know. His brain is not matching his words and actions.