The reason why Myeongdong didn't refuse the guy was most likely cuz if he did, the guy could and might've harmed him or lashed out and it could've turned out worse than what did happen. Myeongdong might also think that he couldn't refuse (even though he could) because he was the one who initiated and gave the paper to the man, and like Chung Oak said, it wasn't a smart idea to not change the location. So in this sense, the uke isn't at fault, for going through with the coitus. But he has a fault, for not changing the location and not thinking ahead. The uke isn't a victim, nor did he cheat. This proves it wasn't consensual that time, but since the strange guy didn't know that and it also seemed like he was hostile, Myeongdong didn't refuse the insert and didn't push the guy away.
The reason why Myeongdong didn't refuse the guy was most likely cuz if he did, the guy could and might've harmed him or lashed out and it could've turned out worse than what did happen. Myeongdong might also think that he couldn't refuse (even though he could) because he was the one who initiated and gave the paper to the man, and like Chung Oak said, it wasn't a smart idea to not change the location. So in this sense, the uke isn't at fault, for going through with the coitus. But he has a fault, for not changing the location and not thinking ahead. The uke isn't a victim, nor did he cheat. This proves it wasn't consensual that time, but since the strange guy didn't know that and it also seemed like he was hostile, Myeongdong didn't refuse the insert and didn't push the guy away.