They need to find out as much as they can as fast as they can in order to arm themselves against the world.
It isn't doing them any favours to thwart their curiosity.
By all means protect them from predators, but protecting them from ideas and images is itself a form of abuse.
Do you really think children are angels? Get real. Have you forgotten everything?
Children are animals.
I was far more depraved at six than I am now.