In a manner of speaking they are blank slates. Else why would they need to be taught values or morals?
Never intended to suggest they be " 'cut out of' the world". But they do need to be taught about the world.
As far as "waiting to write on". That is exactly what the schools are doing. Unfortunately much of what they are writing is not appropriate!
Personalities, yes! But their "opinions require development. Learning the world is a dual task job, that of their parents and the schools. Many parents abdicate to the schools and that is a bad thing. And much of schooling is misdirected.