Eunsung shouldn't be hated on because of this. He was a teenager who lost a loving family. Yes, he was saved, but if you think about it, Taegun had only been there because he stepped on gum and just happened to look up after huffing about it.. So, in all the emotions, of course Eunsung would be pissed that the person who stopped him from jumping only was there because he (Taegun) stepped on gum and happened to look up.