I'd say this is a case of collective stupidity punishing original thought. So I would phrase this exactly as "collective stupidity in authority turning people to mindless sheep".

And why would you have to be an engineering teacher to presume innocence here? This is a school; anyone involved should have been able to clarify everything in 5 seconds, even without the child explaining himself.

Welcome to 'murrica, kid. You better learn to censor yourself.