Because the protagonist has to be so good until she becomes stupid, it's bad enough that she doesn't defend herself as the bi*** with pigtails but she also doesn't let the other characters punish her when she deserves it.
@Martha Elena Brenes Orozco noo its not like that. that girl is engaged to the prince or something so if yuri was to harm her in anyway he would be tried for treason so she had no choice but to stop him. otherwise he could have even faced a death penalty (worst case) for harming a royal's fiancee.
@Shasha when the both of them leave the pigtail girl after the fight someone says something along the lines of if u are engaged to the royal family u should keep ur mouth shut or something like that