Now you are mixing papal infallibility, infallible teaching/doctrine of the church, the roll of the pope in doctrine, how doctrine is developed...  while (in previous comments) grossly misrepresenting the doctrine itself.  We are moving forward here, but still a long way from the actual facts.  But, perhaps the bigger issue is faith, belief and obedience:  yes, that's required on quite a few subjects.  Damn, one just can't do whatever they want, and maybe that is the real rub.