Pet, if you don't trust yourself to properly interpret the Bible, who DO you trust for that?
The church established by Jesus Christ.
It means they trust God to lead them thru their fallible discernment to determine Rome is worthy of implicit assent that means they are not to trust God to their lead them thru their fallible discernment to ascertain the veracity of RC teaching, as Rome is their supreme authority.
Which is why they censure us for interpreting Scripture, under the premise that an infallible magisterium is essential to correctly know which writings etc. are of God, as well as their assuredly correct meaning.
Which is novel, but Rome has presumed to infallibly declare she is and will be perpetually infallible whenever she speaks in accordance with her infallibly defined (scope and subject-based) formula, which renders her declaration that she is infallible, to be infallible, as well as all else she accordingly declares.
Yet in real life what is official RC teaching, as well as their meaning, or aspects of them, often are subject to variant RCs interpretation, as is interpreting the interpreters, that of lower levels of magisterial teaching. Resulting in various sects.
That is what is behind the infallible smokescreen.