I think you are not understanding the term, invincible ignorance.
Of course, one can ask questions but if one is invincibly ignorant of an issue, one does not ask questions to clarify because one doesn't know that there is anything to clarify!
Invincible ignorance is not necessarily a permanent condition. Every one of us was in invincible ignorance of the Immaculate Conception, for example, until we first heard of the doctrine. And, because all of us started out as babies, this condition affected every single one of us--for a time.
There is not one person on this forum who can say he or she truly knew the doctrine of the Immaculate Conception, or indeed, any Catholic doctrine, when he or she was an infant. Furthermore, none on this forum knew to ask questions about doctrine. Your faith, if you had been baptized as an infant, was a supernatural faith that gave you the propensity to be accepting of the true Catholic doctrines as you learned them.
It seems to me that those who reject the concept of invincible ignorance simply don't want to understand what it is: Their ignorance of what it means is truly, as demonstrated above, vincible and, it seems, often pertinacious.