It is a very tough situation. Maybe that child's issues are so severe that this school just isn't suitable for him. If a child is likely to get so upset/angry that he'll lash out and hurt staff or other pupils, then in the absence of having extra straff available to monitor just this one child, the school appears to have no other option than to keep him out of school.
Hard to say if the school's management of this particular situation is poor or not without knowing exactly the circumstances the school found itself in. The parents will of course allege that the school must do more but unfortunately there is a limit to what any school can do in certain situations.
What's strange though is the school having to close for over a week. There are other schools that have to deal with such issues and they manage them with resorting to closing the whole school.
