This inviolable authority was instituted upon whose authority? The magisterium? That's convenient.
"Just Because We Say So" as holy writ. What a concept. Paul rebuked Peter in the Bible. You regard him as your first Pope. He didn't accept Peter's authority in that instance, rather he upbraided and corrected him.
The Church of Rome would do well to accept rebuke and correct its ways as did Peter. Instead, those with legitimate concerns over corruption and immorality and bad doctrine have been met repeatedly throughout history with arrogance and being outcast and even murderous rage.
This is not the reaction of a Godly institution. An institution that won't purge itself of open Sodomites because it puts more faith in it's own "because we said so" as far as their being priests than it does in the Bible that utterly condemns such behavior in any man or woman, let alone one purporting to represent God.
Ah, now we have gotten to crux of your dissent.
It is a good thing there are many, many Protestant denominations and/or others that are not mainstream Protestant that are free of sinners. Please enlighten me as to which have purged themselves and therefore are now made up entirely of non sinners.