It's a little bit more complicated than that. The quote comes from a Papal Bull, Unam Sanctum, written by Pope Boniface VII in 1302 against King Phillip of France.
The quote to which you are speaking is, Furthermore, we declare, we proclaim, we define that it is absolutely necessary for salvation that every human creature be subject to the Roman Pontiff.
Note it says "be subject to" (the authority of)...not that we have to believe each and every utterance of the Roman Pontiff.
As an American Citizen, I am subject to the authority of the United States...I am required to obey the laws. Not that I am required to believe everything that comes out of the government. As a Catholic, I am required to obey the laws of the Church and to believe the infallible "Magesterium" of the Church, not that I am required to believe every utterance of a member of the clergy (from a transitional deacon to my bishop to the Pope).
One thing that a lot of non-Catholics have a hard time with is the concept of Papal Infallibility (sadly, a lot of Catholics have a hard time with the concept as well). Without going into a bunch of theological minutiae, it is not an every day thing and most particularly doesn't apply when a pope opines about global warming, the minimum wage, universal health insurance, or immigration policy.
Never ceases to amaze how Catholics run from this when it’s published. US doesn’t leave the wiggle room Roman Catholics claim. It is an absolute claim to full authority by the pope.