http://www.bbc.co.uk/news/world-europe-14417362

"It is part of the mainstream Protestant Church in the Netherlands (PKN), and the service is conventional enough, with hymns, readings from the Bible, and the Lord's Prayer. But the message from Mr Hendrikse's sermon seems bleak - "Make the most of life on earth, because it will probably be the only one you get".

When it happens, it happens down to earth, between you and me, between people, that's where it can happen. God is not a being at all... it's a word for experience, or human experience.

Wim De Jong says, "Here you can believe what you want to think for yourself, what you really feel and believe is true.""

Mr Hendrikse describes the Bible's account of Jesus's life as a mythological story about a man who may never have existed, even if it is a valuable source of wisdom about how to lead a good life.

Isn't this grand? And yet the "Reformers", though they would be aghast at the fruits their rebellion has caused, have no strict right to, since it is only the logical end of their doctrine of private judgment? If man may decide for himself which books belong in the Bible, why may he not also remove every passage in Holy Scripture he finds uncomfortable? If he interprets it subject finally to no external authority whatsoever, but only his own ever-wavering private judgment, why may he not also interpret the entire Bible as merely mythological?

Apart from Scripture, this is exactly what the First Vatican Council foresaw.

 

Everybody knows that those heresies, condemned by the fathers of Trent, which rejected the divine magisterium of the church and allowed religious questions to be a matter for the judgment of each individual, have gradually collapsed into a multiplicity of sects, either at variance or in agreement with one another; and by this means a good many people have had all faith in Christ destroyed.
 Indeed even the holy Bible itself, which they at one time claimed to be the sole source and judge of the christian faith, is no longer held to be divine, but they begin to assimilate it to the inventions of myth.
 Thereupon there came into being and spread far and wide throughout the world that doctrine of rationalism or naturalism, - utterly opposed to the christian religion, since this is of supernatural origin, - which spares no effort to bring it about that Christ, who alone is our lord and saviour, is shut out from the minds of people and the moral life of nations. Thus they would establish what they call the rule of simple reason or nature. The abandonment and rejection of the christian religion, and the denial of God and his Christ, has plunged the minds of many into the abyss of pantheism, materialism and atheism, and the consequence is that they strive to destroy rational nature itself, to deny any criterion of what is right and just, and to overthrow the very foundations of human society.

  Well, yes. Either God decides or we decide. Now if we are going to decide by our personal logic, then my logic will be different from yours there will be as many ideas as there are people. And as all people claim to be equal their ideas will be equal. And there will be no way to decide which one is correct. Then either of two things happens: 1-those countless ideas wage endless wars 2-they try to accept anything and everything as correct to avoid more wars.
  And some liberal-religious people naively try to reconcile all to all by saying:" but we need some freedom." well, how much is some? who decides on some?

  Unless one lives in a remote jungle, or in any place where church activities and sermons are prohibited or controled, such an ignorance is impossible, especially in todays world with wide access to information.

Daegus,

Objectively considered, Protestantism is a heresy of course. It involves a repudiation of Catholic truth. But this statement may not necessarily be true, as it pertains to their interior disposition  - they may be inculpably ignorant, and so in good faith. If they are ignorant through no fault of their own and are willing to obey the will of God and the truth He has revealed, as best as they know it, then this would not be true.

For the vast majority of people it is true. How many Protestants above the age of reason do you know that don't know what the Catholic Church is or have never heard of it in their lives? How many of them would convert to the Catholic faith if you could prove it was true beyond question? I doubt the number is very high. You also need to consider that external actions are more often than not reflective of the interior disposition of the soul.

On another note, you should be very careful with how you deal with the topic of "invincible ignorance" and the like. Inculpable/Invincible ignorance has never been historically used to apply to Protestants, and it really has only ever applied to those who the gospel has not yet reached. When speaking of those people, they will not be condemned for the sin of unbelief, but will be condemned for other mortal sins. If these people were truly of good will, God would reveal His truth to them in one way or another. Besides, if these people were really invincibly ignorant, they wouldn't actually be Protestants at all, but Catholics who are erring in the faith.

Once a Protestant makes their profession of faith (which virtually of them do or will do at some point), that is when they cease to be members of the Church and make the decision to adhere to a false sect and thus become heretics. If they were truly of good will and "inculpably" ignorant, God would find a way to reveal his truth to these people. Another thing to consider is that the vast majority of Protestants in the world are in places where the presence of the Catholic Church is hardly invisible. The Catholic faith is definitely not foreign to Europe (as it built Europe..) or the North Americas. It is not foreign to South America (for the same reason as Europe), it is not foreign to Australia and it is not entirely foreign to Africa as Catholic missionaries have been proselytizing long before Protestants came about. It is only more or less foreign to the majority of Asia, as Christianity has heavily been suppressed in Asia (this is especially true for China).

In summary, I have no reason to believe that there's anything other than a very small amount of people who are "inculpably" ignorant as you say. Protestantism's existence has its basis in its rejection of the Catholic Church. There is not much of a way to get around that.

Like spouse said, unless one lives in a remote jungle (which Christian ideals would probably not even reach to begin with), it's highly unlikely that such an ignorance happens to very many people, if anyone at all.