I find it a difficult thing to say in today's multicultural world where all must accept all or be condemned as bigots, but we cannot do the diservice to our relatives in Christ (even though brothers and sisters seems much to close to be accurate -- I would more comfortably call them distant cousins).
We must stand up for the truth of God as revealed by the Prophets, as proclaimed by Christ, and perserved unconquerable by the Church Fathers. The Roman Catholic Church has not preserved the truth of Christ without blemish. It has adopted teachings that can only be described as heretical. To coddle them and court them by legitimizing their positions does no one any good. Shake off the innovations of the West and embrace Christ. What more can we say. It is correct they need us, only because we have preserved the true faith; not because we are so charming, or always friendly on this board.
We, Orthodox, are not a denomination, but rather we are those who rightly believe the faith of the Apostles. I am a convert and appreciated the candor of my Priest when he clearly delineated the differences between my false protestant beliefs and the truth of Orthodoxy. I had to humble myself and say, "I have believed and even taught heresy."
This is not to say their can be no salvation outside of Orthodoxy, but this is not revealed to us. The Orthodox Church we know is the true Body of Our Lord; it's sacraments valid and effectual for our salvation.