I don’t buy that story. The school is trying to cover its tracks. No way some low level security guard is going to make that call on his own. He was instructed to take that position by someone in the hierarchy and we haven’t heard the whole story yet. The public school system if full of anti-military wing nuts.
He’s a low level rent a cop. Making minimum wage. He made the wrong call and the superintendent reversed him.
You're probably right. If I had to bet, I'd bet the guard was acting on instructions from a vice-principal, or from the principal.