I actually get that Yuna was trying to make MC realise that he's not strong enough to protect his loved ones from the upcoming threat, just like when he wasn't strong enough to protect Irene. But hurling insults at him and humiliating him, reminding him of his deepest regret and insecurity and telling him that he's just a useless trash who doesn't deserve to be with Irene, Fuck man, that was the bitchiest move on her part. All the while when MC was finally giving himself a chance to move on with new determination.
At the start, even if she was insulting him every time they meet, I still felt for her because of her past but it doesn't give her any right to hurt him like that. After that move I've lost all interest in her.
I just hope that in the future update she'll realise what she did and regret her actions.