Why is Infant Baptism Improper?

There’s one basic fact which eviscerates every claim to its propriety:  the New Covenant is not a covenant of the flesh (like circumcision) which can be imposed on a passive recipient without that recipient’s agreement; it is a covenant of the heart, demanding and requiring the heart’s full agreement.

Given that one simple truth, infant baptism is rendered illegitimate on its very face since it bypasses the active agreement of the heart of the infant.