Because of the differences and disagreements over what is canon and what is not the Bible has been called an errant collection of inerrant works. No Scripture exists dictating which books and works are to be included so God, in his infinite wisdom, gave us a commission of men, directed by the Holy Spirit to infallibly capture preserve, defend and interpret the written Word.
Now you tell us that infallibility is too great a prerogative to be conferred on man even though God made man the organ of his revealed Word, is it impossible for Him to have made man its infallible guardian and interpreter. You also tell us that since the Scripture itself is inerrant and infallible that is sufficient.
How infallibly certain are you that an infallible Bible is sufficient for you or for everyone? Either you are infallibly certain that your interpretation of the Bible is correct, or you are not.
If you are infallibly certain, then you assert for yourself, and of course for every reader of Scripture, a personal infallibility which you deny the Pope, and which we claim only for him. You make every man his own Pope.
If you are not infallibly certain that you understand the true meaning of the whole Bible of what use to you is the objective infallibility of the Bible without an infallible interpreter?
Besides the Scriptures are defined by the word "pure" - "Thy word is very pure" Psalm 119:140. If it is not pure, it is not Scripture. Thus we can completely trust it, meditate on it and Pray it back to God in praise and supplication.
But has not the doctrine of Papal Infallibility has led to the position that Mary's sons were not James, Joseph, Simon, and Judas and has led to override a host of Scriptures (as the beginning of this thread shows).
It certainly has. For if they are her sons, then the Assumption of the Virgin Mary is false and so are a host of other positions.
The real problem is making a Goddess and worshiping her. One whom you say you must go through to get to the Lord Jesus Christ. Whom you say Reparations are due and is Sinless. This is how you make a Goddess.
But the Scripture are clear "All have Sinned and Fall Short of the Glory of God" (Romans 3) and all Mankind falls under that save one, The Lord Jesus Christ Himself. He alone was born of a Virgin so that the Sin and Death, through the bloodline of man, could not infect him. He was begotten not made.
He alone is Sinless and the only one worthy to pay the price for the sins of folks like you and me.
Worship him alone and turn away from this Goddess.