It was clearly shown that Chanwoo isn't aware of his boundaries and has problem with limits. He was nearly strangled to DEATH and he didn't say anything. MD knows that and takes advantage of that. He is mixing his emotions with play which is unacceptable. There is no place for ulterior motives in BDSM play.
Then why doesn't he just quit BDSM? Like wouldn't that be much easier?
It's rather clear he isn't really stable. Also as experienced dom MD should know better than getting advantage of that and making him participate in something he is uncomfortable with.
Most of yall are basically slut shaming him and saying that he deserves it...