Because he don't care about MC feelings. He sometimes act like a boyfriend but he also let on that he sees MC as a whore.
Everytime he is upset he put the blame on MC, that's toxic too. Their relationship is inches away from descending into an abusive one and it's entirely the sundae's fault.
Because there’s an entire episode of him talking about how he doesn’t even like MC lol
There're several chapter where he treats Hanjoo like a convenient hole/booty call even he knew Hanjoo likes him - play with one's feeling. He didn't loose him up properly - Hanjoo felt painful whenever they have sex.
He take for granted
He knows Hanjoo will always chasing him so he let him in. But he wanted to be on the safe side without any real commitment to the relationship although he does crave the affection
Why is everyone against the sunbae? I don't get all the hate