That was my first thought too. Physically restraining a person, especially a minor, and even more especially a minor with trauma, is a very serious thing. It was strange to me the article had nothing about why the girl needed to be physically restrained.
But I'm also more suspicious about it because it's American, I've seen (in the news) so many examples of insane authoritarianism in American institutions, where even doing your hair in a non traditional white manner is considered grounds to be expelled.
And numerous cases of calling the police on children "to teach them a lesson"!!!
American conditions in institutions are insane just like they are in the rest of American society. because USA as a nation has gone more and more sociopathic and authoritarian over the past 40 years. Might makes right is just one issue, and I suspect the one that could have been at play here? It is quite telling IMO that the colleague doesn't blame the girl.
It is also weird that she is just described as "a staff member" indicating she has no special training with these sorts of children!
She may have done her best according to her abilities, but this reeks of an institutional failure.