Yes, that is an excellent quote. And Pius IX goes far beyond the scenario that I mentioned. Anyone familiar with EENS want to comment on what he said here:
"There are, of course, those who are struggling with invincible ignorance about our most holy religion. Sincerely observing the natural law and its precepts inscribed by God on all hearts and ready to obey God, they live honest lives and are able to attain eternal life by the efficacious virtue of divine light and grace. Because God knows, searches and clearly understands the minds, hearts, thoughts, and nature of all, his supreme kindness and clemency do not permit anyone at all who is not guilty of deliberate sin to suffer eternal punishments."
Do any of the people here think Pius IX taught heresy in that statement? If not, why not? Do all the people commenting on this thread accept the concept of "invincible ignorance" as a limitation of EENS? He seems to open up the possibility that "invincibly ignorant" Pagans could "attain eternal life."
So, only the malicious interpret this teaching as some justification of BoD. Pius IX himself during his lifetime got wind of how people were interpreting this, i.e. according to the same interpretation you impose on it here by reading your heretical anti-EENS perspective into it ... and he was furious, denouncing it as wicked slander.
By interpreting it the way you claim, you would make Pius IX a Pelagian, and also a heretical denier of the fact that supernatural faith is required for salvation, that merely not having committed actual sin is tantamount to salvation, having forgotten entirely, as the Pelagians do, about Original Sin.
What he's saying is confirming the principles behind the theory of Limbo, where infants, precisely because they had not committed actual sin are not subject to any eternal punishments. Simply not receiving the Beatific Vision is NOT a punishment, or in Latin even more precisely a
poena, or infraction, which always suggests having done something to deserve it.
What he says at the end is almost identical also to what St. Thomas said, that if there is someone out there who's invincibly ignorant and has not committed any actual sins or done anything that would impede the action of God's grace, God would send an angel if necessary to enlighten them. St. Thomas did NOT say they could be saved in that state, since he affirmed that explicit knowledge of the Holy Trinity and Incarnation are necessary for salvation ... but in fact indicated that it's SO necessary to have the faith that God would send the angel to instruct this individual in the faith. That's all that Pius IX is saying.
I personally have speculated that in addition to infants being in Limbo, there might be others there, such as unbaptized martyrs, where the martyrdom had washed them of any punishment due to sin, so that they would no longer be liable to punishment for actual sin, and even possibly some others who lived lives consistent with natural virtue, with each soul having a measure of happiness and/or unhappiness that corresponds precisely to the punishment due for their sins or else any virtuous acts that may have served to expiate these, at least in so far as their requiring punishment. This is what St. Ambrose meant by his expression that unbaptized martyrs are "washed but not crowned".