You seem to think the school knew about this alleged harassment.
Yes. I do. Moreover they created the entire situation in the first place by involving themselves in a young man's mental disorder and exacerbating it:
King's mother said she pleaded with school officials to help tone down her son's increasingly flamboyant behavior. One teacher encouraged King to explore his sexuality and gave him a dress.
King's mother should sue the school big time. And then McInerney's parents should sue them too, at a minimum to pay for a good defense of the kid that they put through such emotional hell that it drove him to lash out the way he did with their PC game-playing.
The school knew all about it. The other kids were told they had to tolerate King’s insanity.
That is precisely the point here. And it's not simply an opinion. The school, of course, denies responsibility, but the system has already been made to pay some money:
King's family has settled a wrongful death lawsuit against the school district, McInerney, a gay rights organization, a shelter and others. The suit claimed that everyone from King's teacher to his social worker failed to urge the effeminate teen to tone down flamboyant behavior.