The New Testament leaves us in no doubt as to the outstanding characteristics which the true Church must possess. Christ founded but one Church. Its members were to form the "New Israel," or to be God's "Holy People" in this world. These members were to be called, not from one nation only, but from all nations. And those charged with the official duty of preaching the Gospel were the Apostles and their successors till the end of time. This means that the true Church must be one united body, holy, catholic and apostolic.
That impression arises from your confusing the Catholic and the non- Catholic Churches as if they were all equally accredited representatives of the Christian religion. That the Catholic Church denies. And if you consider the Catholic Church in herself you will find quite absent as far as she is concerned the diversity and contradictions of which you complain. Go to any Catholic Priest in Sydney, New York, London, Berlin, Paris, Capetown, Tokyo, Madrid, or in any section of Europe, Asia, Africa, America, or Oceania, and every one of those Priests will tell you exactly the same thing where it is a question of essential doctrinal or moral teaching. That other Churches differ from her and differ amongst themselves is not surprising, for truth preserves unity whilst error inevitably leads to diversity.