As soon as society refuses to adequately intervene to stop the harm, any degree of harm justifies any level of force necessary to end that harm. Your position is only valid so long as society is willing to intercede on behalf of the victim.
The content in question also isn’t actually them.
The content in question is harassment at a minimum. It is harm. Serious harm.
Being violent just because your feeling are hurt is barbaric and has no place in a society.
So long as society is willing to intercede against the harm caused by harassers, I agree. Here, that intercession was explicitly denied. The school refused to act. The school failed to even separate or supervise the two parties. Consequently, society lost its ethical justification for criticizing the victim's efforts to end her victimization. With the school failing to act reasonably or responsibly, we don't get to criticize the victim's actions.