Utter nonsense. Mary was ancillary to the advent of Christ. She was not born without original sin. NOTHING in the scripture points to contrary.
To claim all of the trappings of the Immaculate Conception is to deny why Christ came in the first place. If ONE person can claim that they are without sin, then He died on the cross for NOTHING!
Paul states, unequivocally, that ALL have sinned and fall short of the Glory of God (Romans 3:23).
Christ alone was without original sin because He was not conceived of through mans will, but of God's will!
To claim that those who disagree with IC would deny Christ His divinity is intellectually dishonest and, IMHO, blasphemy.
You simply know very little or nothing of the teaching of Immaculate Conception.
Then Jesus sinned according to that logic. ALL = ALL unequivcally.
Well, no.
Mary never claimed that she was without sin.
The doctrine of the Assumption is based on a sacred tradition that reflects an understanding of Mary's nature that dates back through the centuries.
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.