Okay, so you are saying the Church changes Her teaching on something? Yes, or No?

Let me explain then. Nearly everyone in the Church taught geocentrism for over a millenium. And then nearly everyone in the Church taught the opposite. Obviously only one opinion is official Church teaching and one is an error, but both opinions were tolerated by the Church at different times. The same is true in the infants without baptism suffering fire in hell or not. Different opinions were allowed at different times but only one can be official Church teaching.

No, I am saying the Church sometimes can allow errors to be taught by her members without always condemning them.

Okay, now you feel compelled to explain. The point really is that what was taught was NOT against previously defined solemn dogma. Do you understand that?

"By way of answer let my first proposition be: Before the barbarians heard anything about Christianity, they did not commit the sin of unbelief by not believing in Christ. This proposition is precisely that of St. Thomas in Secunda Secundae, qu. 10, art. 1, where he says that in those who have not heard of Christ unbelief does not wear the guise of sin, but rather of punishment, such ignorance of things divine being a consequence of the sin of our first parent. "Such unbelievers as these," says he, "are indeed open to condemnation for other sins, ... but not for the sin of unbelief." 

"This proposition is opposed to the teaching of many doctors and especially to that of Altissiodorensis, 3 p.,^[10] on the question, Utrum fidei possit subesse falsum, where he says that ignorance not only of Christ, but of any article of faith is not invincible ignorance in any one, for if a man does what in him lies, God will illuminate him either through the doctor that is within him or through a doctor outside, and so it is always a mortal sin to believe anything contrary to articles of faith. He takes an illustration from an old woman to whom a bishop might preach something contrary to an article of faith. And he lays down the general proposition that ignorance of divine law excuseth none. William of Paris was of the same opinion and supported it by the same kind of argument. For either, says he, such an one does what in him lies and therefore will receive illumination, or if he does not this, he is without excuse. And Gerson (De spirituali vita animae, lect. 4) appears to be of the same view. "Doctors are unanimous," says he, "that in matters of the divine law there is no room for invincible ignorance, seeing that God will always help him who does what in him lies, and He is ready to enlighten the mind as far as will be necessary for salvation and the avoidance of error." And Hugo de Sancto Victore (^[11]bk. 2, pt. 6, ch. 5) says that none is excused by ignorance for breach of the command to receive baptism, for he could have heard and known, had it not been for his own fault, as was the case with Cornelius (Acts, ch. 10)."

"I say accordingly on this point that negligence with regard to the subject-matter is requisite for ignorance, even though it be vincible, to be imputed as, and to be, a sin, as, for example, that the man refused to hear or did not believe what he did hear; and on the other band I say that for invincible ignorance it is enough that the man bestowed human diligence in trying to learn, even if in other respects he is in mortal sin. And so on this point our judgment is the same concerning one in sin and one in grace, both now and immediately after Christ's coming or after His passion."

"But the mistake which the doctors in question make is in thinking that when we postulate invincible ignorance on the subject of baptism or of the Christian faith it follows at once that a person can be saved without baptism or the Christian faith, which, however, does not follow. For the aborigines to whom no preaching of the faith or Christian religion has come will be damned for mortal sins or for idolatry, but not for the sin of unbelief, as St. Thomas (Secunda Secundae, as above) says, namely, that if they do what in them lies, accompanied by a good life according to the law of nature, it is consistent with God's providence and He will illuminate them regarding the name of Christ, but it does not therefore follow that if their life be bad, ignorance or unbelief in baptism and the Christian faith may be imputed to them as a sin."

St. Columba preached and worked miracles among the Picts, and, though he spoke by an interpreter, he made converts. One day on the banks of Loch Ness he cried: Let us make haste to meet the angels, who are come down from heaven and await us beside the death-bed of a Pict, who has kept the natural law, that we may baptize him before he dies." He was then aged himself, but he outstripped his companions, and reached Glen Urquhart, where the old man expected him, heard him, was baptized, and died in peace. And once, preaching in Skye, he cried out, "You will see arrive an aged chief, a Pict, who has kept faithfully the natural law; he will come here to be baptized and to die;" and so it was.

New Catholic World (1867) pg. 668