Who should bear the majority of the responsibility for this sexual attack on a 5 year old girl in a school bathroom?

A Jelly, who isn’t very active any more, texted me this morning and asked me to ask this.

In a nut shell, ”…the Education Department is investigating whether a Georgia school district’s trans-inclusive bathroom policy created a “hostile environment” for a 5-year-old.” The policy allows students to use what ever bathroom they want at any given time. Here is the article

The allegations are that a gender-fluid student, who is male by anatomy, attacked 5 year old girl in the girl’s bathroom, pushed her against the wall, and assaulted her, hurting her genitals.

Another article by the Epoch Times says the school contacted DFCS and reported the girl’s mother. They suggested the mother assaulted the girl then made this story up to cover it up.
In your opinion, what can / should be done? Could it have been prevented it in the first place? How?