There are many who rightly claim that authority is at the core of issues concerning Christian (dis)unity. Protestants, in particular, will not accept that there is any person on earth who holds universal (e.g., catholic) authority, in the form of the papacy. I can imagine Protestants being somewhat incredulous that Catholics would dare to take seriously such lines as "do whatsoever they tell you but practice not what they do" or "he who hears you, hears me" and of course, "he who rejects you, rejects me". I hardly fault them for their sense of right and wrong, however. To some extent, everyone can smell corrupt teaching or leadership. But it is not necessarily true that there exists some God-given authority for the sheep to pull down their pastors -- nor the institution of pastoring.
Anti-papacy is at its heart a form of despair. It is sadly born from true concerns about corrupt leaders who failed to uphold the truth, but for the sheep to take matters into their own hands is, to me, a resignation in despair. One has to have failed to see that the Lord promised perpetuity to the Church, and authority to her leaders, while starkly leaving no stipulations on what to do with corrupt leaders. That does not mean that he would tolerate them, of course, but look at the bigger picture: the Lord gives remarkably absolute authority to the leaders of his household, insists upon one of them a particular task to watch and feed his flock, but leaves no word as to how the flock may pull him down along with the other pastors when they misbehave. Why the omission?
Because the Lord reserves for himself the task of pulling them down when necessary. The Lord raises up and tears down. As David maintains of then incumbent King Saul, it is not up to anyone to "lay a hand on the Lord's anointed." David's heart was not deceived by complacency nor was he shirking responsibility. On the contrary, while he could have taken action, with King Saul falling within his power, he saw that he should not have to. Hounded by Saul, still did David's trust in God win out against fear and anxiety. Had Luther, Calvin, Zwingli and other Protestant reformers kept to such trust and hope, what a Church we would have had, reformed and still whole. The same can be said about present day protestants inside the Catholic Church whose anxieties have overturned their trust in God's sure hand, resulting in a sad mix of zeal, bitterness and, in believing that their own hands alone will bring about reform, arrogance. And since the Lord never gave instructions about where to bring grievances against the Church itself, it has been far too easy to believe that the Church was not built on Peter after all.