It's an anti-Catholic term, but Pius IX used it. Yeah right.
Again, you're missing the point. His use of the term caused confusion, which he regretted, and it caused him to re-clarify.
Your first paragraph asks complex issues.
It's not complex, it's directly from Scripture.
Scripture = God enlightens all men who come into the world.
Doctrine = God's existence is provable, to all men, by way of human reason.
Scripture = All men have the natural law written on their hearts. Ergo, no one is invincibly ignorant of God, nor of the 10 commandments.
Doctrine = If they co-operate with grace, and follow the natural law, then any ignorance of the Faith will be enlightened.
Scripture = God does not "cast pearls before swine" and will not enlighten those who, due to their sinful lives, will not appreciate spiritual things.
Ergo, no one is created in invincible ignorance of God or their requirements due to Him and their neighbor. There are only those who are ignorant of the Faith, which ignorance God will cure, if they follow the 10 commandments and seek the truth. Such ignorance of the Faith is temporary, or permanent, depending on the person's cooperation with actual graces (i.e. following of the natural law).
For the 2nd time...you have not admitted that Bl Pius IX was quoted out-of-context in his statement where he mentions it. He later clarified his view, but the modernists who surrounded him had already spread the original mistake far and wide. Do you or do you not accept Bl Pius IX's correction?