That's not true.
In no home the highly complex language like that of a sacred text comes before the basic notions of what is good and bad in child's daily life are.
An urban Jewish child who has never seen a murder or heard of a murder or understood the causes of murder comes to understand that beating another child because of his/her race is evil. No need to know the Ten Commandments.
Totally ignorant. The Law of Moses given to the Hebrews instructed the children of Israel in every aspect of their life and living. Thus, children from an early age were taught the Law of Moses as commanded by God.
5 And thou shalt love the LORD thy God with all thine heart, and with all thy soul, and with all thy might. 6 And these words, which I command thee this day, shall be in thine heart:
7
And thou shalt teach them diligently unto thy children, and shalt talk of them when thou sittest in thine house, and when thou walkest by the way, and when thou liest down, and when thou risest up.
8 And thou shalt bind them for a sign upon thine hand, and they shall be as frontlets between thine eyes.
9 And thou shalt write them upon the posts of thy house, and on thy gates.
Deut 6:4–9.
In other words, God's Laws to the children of Israel were to be talked about every waking moment of their lives. Repetition is, after all, the mother of all learning.
Putting away childish things does not include considering "good" to send a person to a gas chamber on the basis of race.
Jesus, who you say you love, asked us explicitly to be as a child in order to enter the kingdom of God.
So, what is there in children that we must preserve to adult life?
That's exactly what God did in choosing Abram the HEBREW and his Hebrew seed to be the recipients of God's eternal life.