Except all Kang Jun did was tell him who he was. He was taken by surprise but still reciprocated. We could clearly see and read his thoughts and how confused he was about kissing "his friend". While you are right about Kang Jun becoming an ass, it was Siwon that got the crooked ball rolling and snowballed. I like how being drunk and a loose drunk gives the drunk the pass to get away with everything, just like in drunk driving. I was under the influence so I didn't mean to hit them with the car, or punch someone, or rape someone or in this case kiss someone. Not excusing Kang Jun But Siwon shouldn't get a free pass. Kang Jun still had the really messed up childhood and had no relief from either parents. At least Siwon had mom. And regardless Siwon was pretty ignorant even when being shown things and slowly being explained. He wouldn't listen. Siwon owes a big ass apology to Kang Jun. It's never okay to use someone's sexuality to make them feel like shit. That makes them a crappy human being. Especially when he kissed him first. Didn't know being drunk made you gay. Lol
Being drunk doesn't give you a free pass when you're in the habit of drinking lots all the time but we don't know whether Si Won is in the habit of drinking that much. That time he drank because because it was a game (which Jun/Jinha was also participating in) and because his friends ganged up on him, picking him in every round, and this all happened right in front of Jun/Jinha's eyes, so he was aware of al of it. I'd say Jun/Jinha doesn't have much experience hanging out with people in general, let alone with hangover people, so he didn't understand the effects alcohol could have on someone's knowledge and interpretion of events and that's why Si Won was so confused and misinterpreting everything.
...while everybody is cheering, "Finally", and "now we an get smexy times", I am...unsatisfied. Kang Jun has suffered way more and Siwon gets a pass for being drunk? No apology for making the first move while being drunk, forgetting him altogether after kissing and then calling him all those homophobic ignorant slurs? Instead he asks, "why me"? What??? Kang wasn't going to attack him till after Siwon in hi drunken stupor attacked him. ignoring him triggered Kang into lashing out. I hope the next chapter addresses these issues or Siwon will def, TO ME, go down as one of the worst ukes ever! （￣へ￣）