This is the kernel of your error.
CHRIST linked the power of CHRIST to Mary, when he became incarnate through her, and chose, in obedience to the Father, to redeem us through his Incarnation.
That's really right at the heart of the Gospel. In fact, St. John calls those who deny Christ come in the flesh -- and Christ came in the flesh through Mary, remember -- he calls them antiChrist.
That doesn't "make the work of Christ insufficient". That IS the work of Christ.
Before you call something "demonic", stop to remember that "demonic" is exactly what the Pharisees called Jesus.
What does "linked" mean in this statement?