There are five billion people on the earth, and a likely equal number who have ever lived: all of us assuredly have sinned and have benefited from Christ's salvific death and resurrection.
The Immaculate Conception is like a precursor of - or a doorway to - the Incarnation: God entered our reality as both God and Man: he couldn't have become Man without a sinless Mother.
For if humanity had lost sanctifying grace, how much less could it receive God Himself, the source of that grace? Therefore God made Mary free of Original Sin so that she would be a suitable vessel, ark, portal, gateway for Him to enter humanity.
This is why Mary is often depicted as the new Eve: Adam and Eve were both created with sanctifying grace (i.e. they had no Original Sin when they were created). But Adam and Eve lost that grace: and their descendants lost it too. We regain it through Mary in the Body of her Son, Jesus.
The Incarnation is the central reality here: The Immaculate Conception is merely the frame of the central, history-shattering mystery that is the Incarnation. The great mystery of the Incarnation is - almost in passing - the reason for the much lesser mystery of the Immaculate Conception.
We shouldn't attempt to divorce Mary's divine gift of sinlessness from the Incarnation: the one is a small piece of the other. It would be bizarre to talk about Mary's gifts and graces without first recognizing that she is the Mother of God Almighty.
To the contrary: he couldn't have become Man WITH a sinless Mother.
Poor logic and it is adding to scripture what cannot be added since it delves into heresy. With God all things are possible, His revelation in scripture tells us precisely what we need for salvation. Not one word is written that speaks of ANYONE other than Christ, leading a sinless life. To say Mary was the second to do so is fundamentally wrong because it contradicts scripture.
Therefore God made Mary free of Original Sin so that she would be a suitable vessel, ark, portal, gateway for Him to enter humanity. God has used sinful man in myriad ways, He even used Pharoah to be His vessel. Do not put the Almight in a box that He cannot emerge from.
We regain it through Mary in the Body of her Son, Jesus. Pure heresy. Only Christ redeems. Grace is given by God alone, not Mary.
Mary's gifts and graces without first recognizing that she is the Mother of God Almighty.
But she is NOT the mother of God. She is the mother of Jesus, the man. God has no father, but Christ made Himself subject to the will of the Father.
Hbr 2:7-9 You made him a little lower than the angels; you crowned him with glory and honor and put everything under his feet." In putting everything under him, God left nothing that is not subject to him. Yet at present we do not see everything subject to him. But we see Jesus, who was made a little lower than the angels, now crowned with glory and honor because he suffered death, so that by the grace of God he might taste death for everyone.