Judaism never looked on children as innocent and pure.
They were never considered little angels.
On the contrary, they were considered liable to sin and cruelty out of ignorance.
Man is not born human; he comes into the world as a wild young creature.
As he grows, he may become tame.
His wildness as a child is a result of not grasping the existence of the other.
It is ignorance, a lack of knowledge, that makes empathy impossible.
–Rabbi Adin Steinsaltz