For example the Eastern Church, and the Protestant churches are at odds with a fairly recent (1854) Catholic proclamation about a new Catholic doctrine called "the immaculate conception" which is generally regarded to be unscriptural.
Because of the Pope claiming to speak for God, such anomalies can't easily be corrected. It is one of the sticking points against the reunification of the Roman Church with the Eastern Church, after the schism of 1054.
Nichols has thought this through. I like his use of the term “tolerated concubinage.” Must remember that one.