If it were real and not the ephemeral writings of hundreds of popes, some of which cared more for governing Rome than being vicar of Christ, you would have a point. In recent times popes try not to contradict each other, which is a shame, because some do make errors. The onlyh infallibility of that is God does not hold those who obey responsible for such foolishness. It seems Jesus thought a bit of relativism was essential.