The fallacy of original sin

The concept of original sin is not found in Judaism!  Instead, God says “the imagination of man’s heart is evil from his youth.” Youth, here, is derived from the word na’ar, referring to a male old enough to be a warrior or get married.  Judaism does not ascribe to the belief that infants and young children are capable of sin.  The Proverb so frequently quoted:

Foolishness (folly, impiety) [is] bound in the heart of a child (na’ar); [but] the rod of correction shall drive it far from him.

is actually referring to teens, at minimum.  Na'ar is a masculine Hebrew word that conveys the idea of being shaken off.  It is used twice to refer to younger boys (Moses and Samuel, respectively) because the term applied in their situations, but at the time was generally understood to refer to what we would call a young man.

The Hebrew word for sin is khata, meaning going astray.  It is also used as an archery term, missing the mark.  

Sin is a act, not a state of being.  It is a conscious choice to commit an act contrary to God or God's divine instruction, a deliberate choosing to disobey.  But God is gracious in His expectations of obedience.  Shema is the Hebrew word for obey, but it doesn't mean compliance as we so often use the word obey.  Instead, shema has the concept of hear, understand, obey.  It stands to reason that if I do not hear God's instruction, I cannot obey.  Also, if I hear, but do not understand and therefore do not comply or comply imperfectly, God doesn't consider my actions to be sin.  I can't go astray or miss the mark if I do not comprehend the path or have a mark at which to aim.

Judaism holds that atonement for sin is done through the right action. 

“One time, when Rabban Yochanan ben Zakkai was walking in Jerusalem with Rabbi Yehosua, they arrived at where the Temple now stood in ruins. "Woe to us" cried Rabbi Yehosua, "for this house where atonement was made for Israel's sins now lies in ruins!" Answered Rabban Yochanan, "We have another, equally important source of atonement, the practice of gemilut hasadim ("loving kindness"), as it is stated "I desire loving kindness and not sacrifice" (Hosea 6:6).”

Jesus fulfilled Judaic law and tradition when He atoned for all sin through His sacrifice.
  
So now there is no condemnation for those who belong to Christ Jesus.  And because you belong to him, the power of the life-giving Spirit has freed you from the power of sin that leads to death. (Rom. 8:1-2)

Why, then, do we assume the worst in our children, then force them to atone for their sins through punishments of physical pain or deprivation?  All actions have consequences, yes, but going beyond those consequences into the realm of punishment makes a mockery of Christ's sacrifice wherein He took all the punishment for all sin, for all time.