Any thing less is Eisegesis.
1 Peter specfically says that you must be baptized to be saved. How can a child be saved other wise? are you prepared tosay that every child that dies before baptism is in Hell?
If you have no understanding of right or wrong, no comprehension of cause and effect, how can you sin? A baby is born perfect, and innocent of sin, and remains so until he reaches the age of reason.
When you know right from wrong, and consciously chose to do wrong, with full understanding - then you have sinned.
A child at the age of 12 understands the basics of right and wrong, and chooses. They are held accountable for their transgressions. But a baby can neither comprehend what a sin is, promise to stop committing that sin, understand the concept of remorse nor vocalize to acknowledge either guilt or forgiveness. Thus, they are the purest souls on the planet.
It’s just that simple. Because they do not understand, they are saved. This is part of Christ’s atonement.