PUBLIC APOLOGY
I am sure that somewhere on this site I called Cardinal Gibbons a heretic, but I'm not sure where... I retract that with the deepest apologies. Granted, he was publicly and vocally in error with his Americanist views. However, the Church never called him a heretic, though chastising his Americanist error.
I also no longer believe the Baltimore Catechism is heretical though there are some things that still sound a bit funny in there, it's the wording of it more than the actual ideas.
I am not sure why it is important to believe that the false religion you are in is the true religion; except that perhaps that is how the authors of the catechism defined invincible ignorance; being invincibly ignorant that false religions are false... Since there is no official definition of how far invincible ignorance extends, it is not heretical.