Why do people always talk about unifying the Christian Church...?

Jesus said following His path would be narrow and few would enter in. Roman Catholicism is a rather large group of people, this does not equate with spiritual success. God wants us to follow the guidelines set up in His principles and not the principles of some other men (popes..etc...) who claim to recieve additional teachings from God. God does not contradict Himself. Roman Catholicism has beliefs and doctrines which are not in agreement with the teachings of God. God has stated this before even with the Israelites, that they were more concerned with keeping rituals and traditions of men, and missing the simple truth of the gospel.