Agree, that was a trash coach moment
I agree with you, but I don't think that applies here. Do-yoon said so himself that he has been having trouble at his current weight class so I think the coach is genuinely trying to help him by changing his weight class. His skills could possibly flourish against smaller fighters.
I had a coach like that who made us all cater to the star player. During the competition she couldn't perform well but somehow I performed very well and exceeded everyone's expectation and even though our team lost I got selected for camp, my coach then when to the selectors and made excuses about how I won't be able to make it and take the star player instead, he informed me about this while our way back home, I quit the next day.
Wait didn’t he go up a weight class? So he needed bigger fighters?
Oh wow, wtf, what sport were you playing ?
Yes, I understand that. But he should have brought them both in at the same time, so an misunderstanding wouldn't have been created. Especially when you have one that's moments away of entering a competition. Because now he's under the assumption that he's being moved out for another to take his place. The topic of discussion involved both of them. The coach just wasn't being a great leader. Though there is understanding why he did it, his execution lacked empathy on how it could effect his players mental state and their relationship as a team.
Volleyball
I hate when coaches make unnecessary problems between teammates, than be looking around wondering why they don't get along. In my opinion that's not a good coach.