Well, first, consider that we believe the Holy Spirit guides the papacy in matters of faith and morals. You say we have heretical popes, but we say we don't. Your basis for this is that the brand of Christianity you adhere to has different beliefs. That's understandable, but consider, too, that your viewpoint stems precisely from these differences. How do you know that YOUR confessional group is not heretical. It's a "frame of reference" problem, isn't it? "You say he's blatantly out of line with scriptural teaching," we say he is not. Prove that he is outside of your own authority, or that of your own pastor's.
The papacy, from a simply human viewpoint, has been remarkably consistent over the centuries. That should say something. We don't "blindly trust" the pope, we trust his doctrinal teaching because we know it is guided by the Holy Spirit. Why do you wonder at this, when you feel that you yourself, indeed, all believers, are so guided? How is it blind, lockstep trust to have allegiance to one man following the Spirit, and perfectly okay for you to say that the Spirit leads you, and thus you can automatically follow your OWN inner voice?
The fact that millions of people believe that, and suffer the consequences of massive division and chaos of belief, speaks volumes and should tell you a great deal.
Your church has never had a heretical pope. Is that what you are saying?