There is no way to know what would provide an alternative result, but there are many ways to create an environment that is safe for the student in question snd other students, which by going by comments in the mentioned articles, this was not.
The fact that this child had issues before in the school and that other children had to witness furniture thrown or whatnot is not acceptable for any of the kids.
The school could have provided a one on one to shadow the child if that was an option in their discussions, but after all of what we know that has happened, not doing anything or simply having the parents accompany the child in question is not nearly enough for the other children nor for this boy, whose needs were obvious not being met either.
My point was that sending him to another school is a 'solution' i have never heard used by any school, nor do i see the logic, unless it is a specialized school. In any case, school admin have really let down all involved, as their certainly are ways to deal with children who have special needs (at least in the states where i have taught)