And the conclusion extrapolated from this is that this makes the magisterium of Rome perpetually infallible whenever and whatever it speaks universality on faith and morals, but which is a conclusion that is not warranted by its premise.
And the typical argument behind it is basically that being the inheritor of Divine promises of Gods presence, and preservation, and the steward of Divine revelation and under whom writings were established as Scripture and truth preserved, requires assured infallibility or renders that body to be so.
But which is not what we see in Scripture.
The conclusion is that there was established a hierarchy in the Church and authority - not each individual, not a democracy.
Christ is the head, the Holy Spirit guides His Church as the pillar and foundation of truth.
This is scriptural. Sola scriptura is not.