This is a common misunderstanding of papal authority. (Papal Infallibility - Catechism of the Catholic Church)
Yes, Christ is the Head of the Church, which is His Body.
But the Pope has a unique role in Christ's earthly Church.
The Bible tells us that Jesus is the King of the eternal and redeemed Davidic Kingdom. (Luke 1:32)
In the ancient Davidic kingdom, the palace majordomo served as the representative of the king (or vice-regent) in the king's absence. (Isaiah 22:15-25)
The authority of this office was represented by an over-sized key which the vice-regent wore around his neck. (Isaiah 22:22)
As the King of the eternal House of David, Jesus holds the Key of David. (Rev. 3:7)
And Jesus gives the "keys of the kingdom," representing the office of the vice-regent of the eternal, redeemed House of David, to Peter.( Matthew 16:19)
Few Protestants seem to be aware of this.
Oh, really? Or could it be they've read the text for themselves and determined that all of the Apostles were given special privileges - that binding and loosing thing? So unaware may not be the best descriptive term but instead "disagreement with Rome" might fit.