Protestants believe the first Pope possessed the charism of infallibility. Now, they might not believe that Peter was the first Pope (which he was), but they believe that his Epistles are infallible. They also believe that Luke, Matthew, Mark, Paul, Jude and John wrote infallibly. They believe that Moses "was infallible," too. And Hosea, Micah, Nehemiah, Isaiah, David, Solomon, Zechariah -- any Patriarch, Prophet, Apostle, or Evangelist who wrote a Bibilical Book is deemed by Protestants to be infallible. But somehow they see things as having changed, and the idea of the gift of infallibility being given to man is laughed off as "Popish superstition" at best, and as "Romish sacrilege" at worst.
No, "Protestants" do NOT believe Peter nor any of the other "writers" of Scripture were infallible, only that what they wrote down under Divine-inspiration is infallible. It is the word of God, itself, which is infallible, not the man God chose to pen it. And just because God chose them, does not mean whatever they say outside of Divinely inspired, God-breathed Scripture is infallible either. It is no different today and we still have the Holy Scriptures as God's infallible truth revealed to mankind. IT is our standard and authority because it comes from God.
Amen....!