@elhessan A twelve year old child was ABSOLUTELY scapegoated. If they just wanted to take the head of the guy at the top that'd be semi-reasonable. Especially with proof he was allowing it or causing the problem. But this child is as much at fault for how bad things got as the maids in the palace. All the change she has managed to cause so far was basically just keeping ONE MAN from being sent away to a far posting (A acceptable concession to make for a child) and letting him get his own affairs in order to prevent them sending him away later and then HE did all the moving instead of her. She literally GAINED the ability to influence politics through being kind to one person, and then his misunderstandings on what she says and his desire to serve her well led him to manipulate others around him in that direction. Since then she has also managed to help ONE family personally without that man moving to do things for her.
In this case if she realized that something was happening she COULD have stopped it, she is the princess of their home country even if she has no power the other children there would assume that they can move up by befriending her or be shoved down by making her an enemy. This is why he thinks she could have caused it since it'd only take a few words on her part to get someone attacked for her. But she didn't care about what was functionally a commoner with no relation to her and so didn't seek out the perpetrator even after it happened, meanwhile her own actions of single mindedly aiming for Sion cut her off more thoroughly from any other student in the academy especially since he hated her for not have sought justice in this instance or others because he sees the act of not fighting for justice to be an act of evil in and of itself. Convinced of this evil by apathy on top of his right hand man's thought that she might have caused it he then would spread such a thought to the remaining two people who already didn't have GOOD impressions of her. Like hell, look here at how she was damn near convicted of it despite having ,seemingly, done good things all over and being called an incredibly wise and charitable princess.
And then yeah like RamenRider said, there's SUPPOSEDLY adults in this school that run things, and they AREN'T adults from her nation. That 4-8 people can apparently just break into a room, ravage it, go out carrying a dress, kidnap a woman and her maid, and then trap her in a tower that exists for.....reasons? is fairly absurd. Especially on a 'important' event day when they should be up-ing security all over. Go find the guards they apparently bribed to let this happen, then the culprits and blame them. They'll probably point upwards to try and shift blame but at least then they'd have evidence even if false. They just pointed at her and let everyone below get away with it seemingly. And then later apparently killed her entire family and locked her in a prison to murder later when the unrest went up again?