I can understand. The things they actually did to Meru was only 'justified' and 'treated lightly' was because of Meru's extraordinary capabilities. If it were any other normal student, that person might have suffered physical (and mental) injuries or worse.
And to add, since they actually experienced something as horrible as what that senpai did to Hotaru, they should have known what the consequences of their actions are going to be. So much for being 'smart' students.
Because seriously, what kind of 'proper' people would gang up on a new student who just wants to make a better life for her friend/s in school? If they don't trust her, then investigate on her, duuuh. They have all the means to do so.
And using another innocent student (Chiyo) to threaten her???
I'm not really shaming the manga, but realistically speaking, similar situations like this do happen. Not every victim is going to be like Meru who can somehow protect herself. Not every bully can have a tragic backstory to help them 'justify their deeds, but it's sad how bullying can go so far :((
Not to say that perpetrators should not be blamed for their actions, but if anything, they need all help they can get so that their past traumas and problems can be resolved and help them repent for their actions.
The manga's great and all and I really love it, but I just can't get over the fact that what those three did was done away easily. I mean, even if they suffered such a horrible experience, what they did to those innocent students just can't be justified for me that easily. :(