Does not the doctrine of invicible ignorance apply in the following hypothetical?
A boy is born into an Evangelical household in rural Tennessee. He is raised in such a way that he fears Catholicism; he is taught many falsehoods (Mary worship; saint worship; pope worship), and so on. He never sets foot in a Catholic Church throughout his childhood and adolescence.
Being not especially motivated, he does not do well in school. His public school curriculum does nothing to edify him about the Church or its history – in fact, many things he learns reinforce his beliefs (Crusades; Pope Joan legend; Inquisition; Vatican inaction during the Holocaust). He does not go to college, but ends up taking over his father’s automotive shop.
He works 16 hour days, gets home in time to have some dinner and watch a little TV before he goes to bed – never any time or energy to read.
One day, he sees a Rosary hanging from the rearview mirror of a car he’s repairing. The customer sees our guy notice the Rosary and roll his eyes in contempt. The customer says, “I guess you’re not Catholic, huh?” and our guy responds, “No – I’m a Christian.”
The Catholic – faithful, but not well-read – tries to start up a discussion, but is overmatched by our mechanic’s ability to spout Scripture that “contradicts” the Church’s teachings – things he’s been taught and has repeated for over 20 years – and the Catholic gives up and says, “I guess we’ll have to agree to disagree.”
Then, a meteor plunges directly into the building, utterly destroying it and the two would-be apologists.
OK, I’m being a little extreme here, but truly the point is valid: if our guy’s only exposure to the Truth is through a Catholic who is ill-equipped to illuminate it, doesn’t that constitute invincible ignorance, given the depths of his indoctrination?