If you follow that thinking logically, you'll realize that is the very reason that the whole idea of a Pope is dangerous. Because the Pope has absolute authority over the Roman Catholic church, he is free to define what scripture means and what it doesn't. As we have seen throughout history, as Popes change, so do various church doctrines. Scripture is our authority, not the Pope or any other man.
The Pope alone does not make any changes in doctrine. It is the Pope along with the Magesterium, the Cardinals and leaders of the Church, who make changes, or declare a doctrine infallible. There have been very few changes in doctrine, and the basic ones have never changed, though there have been a few added along the way.
"If you follow that thinking logically, you'll realize that is the very reason that the whole idea of a Pope is dangerous."
Matthew 16:17-19
And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.
And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
Are you arguing with Jesus?
St. Peter was given authority to bind and loose on Heaven and Earth. The office of the Pope is no threat, indeed the only threat it could pose is to people twisting Scripture to fit what they want it to mean as opposed to what it really means. Obviously Christ had faith in this office, why don't you?