Tf is wrong w him

So this is what another person said “ So a lot is skipped out on from the novel but basically Minjun has a pretty bad potty mouth and cusses a fuck ton in Korean so that Daiki doesn’t understand it. However, Daiki acknowledging him in Korean shows that he has understood all of his insults and Minjun is embarrassed. That’s why he gets mad at Daiki for not telling him he understands”

Well that's his own fault to cuss out loud ..why is he taking them out on poor daiki? He should be happy that he ain't dead