I am observing the real authority of the Church, the Holy Spirit. When he is present, it is obvious. Where it is not, is also obvious with those who know him. How do you know him? You have a relationship with him.
When the Pope condones sinful behavior and grants indulgences then he is sinning. All people are guilty of sin but Christ. The Pope is no different. Peter was no different. Paul admitted he was a sinner.
The problem is that God is the authority over the Church. When the two differ, God's Word is the truth. Anything else is sin.
If your Church chooses to accept gay marriage as fact ignoring the teachings of the Bible, how would you justify being a part of it? Also If a Pope blessed Nazi guns, could you stand by him still? If you found out that one or more had killed somebody after achieving the position? Is this man truly infallible? Or just a sinner like the rest of us only with more power?
Personally, I don't see anywhere Jesus requests a stand-in. The Pope to me is just another powerful old man sitting on a throne. I'll never have to answer to him. It will be God I'll have to answer to in my afterlife. The man today in the position of Pope may be a good guy, maybe not, I don't know him and I never will. I do know that Popes in the past have been corrupt just like any other powerful man in a position of almost absolute power. To deny that is to deny his humaness.
The whole reason Jesus came in the first place was to be a bridge between Heavan and Earth. Why is it then that the curtain of the holy of holys was torn? What was he saying? Why tear it just to have a Church bebuild it again? If you don't know what it is like to experience the Holy Spirit in person, then you are missing the whole reason for being in his presence and there must be some other reason for you going to church.