[Tantumergo]

"Oxymoron? You mean like the "infallible teachings of the Pope"?"

Nope - no oxymoron here because this doctrine acknowledges and hinges on the very fact that causes all the problems for "sola scriptura":

AUTHORITY IS PERSONAL BECAUSE GOD IS PERSONAL.

You can never devolve a person-dependent attribute onto an inanimate object - even where that object is scripture itself.

[Iowegian]

No difference, you just trust someone else, i.e. the Pope, to tell you what "the truth" is. The Pope is a person- fallible (as history proves). Just as we all are.