Catholics shouldn't get all that worked up about being called *ignorant*. After all, they don't have much problem calling non-Catholics *ignorant*.
Does the term *invincibly ignorant* ring a bell?
Sure. But the term applies to no one on this forum, so I’m not entirely sure how it’s relevant.
Does the term *invincibly ignorant* ring a bell?
I'm not Catholic and don't presume to speak there, but here I can think of a distinction, even without invoking anything specifically Catholic-related.
"Ignorant" and related words can be used neutrally or "negatively." (I suppose that in some cases it may even be used "positively," though I've never seen such a use. But as I've seen similar things, like "I'm proud to say that I've never watched [insert name of TV show here] and have no idea what you're talking about," I would be amazed if someone else has seen an example.)
A phrasing like "you are ignorant of this"--at least in my experience--is almost invariably negative, since there's usually the implication that the ignorance marks a failing in the intellect or goodness of the accused, such as "if you were smarter, you would not be ignorant about this" or "if you were a better person, you would've made sure that you were informed about this." In fact, if anything, in this regard "invincible ignorance" is somewhat of an opposite, since it seems to refer to ignorance that comes without such a failing.
(I also notice that the Religion Moderator profile says, "When in doubt, avoid the use of the pronoun 'you' and Freeper's names - or put yourself in the other guy's shoes." I'm reminded of the fairly common advice to avoid "'you' language" in certain cases. I've found this advice to be useful.)
Also: be careful of using such reasoning as I quoted at the top (we recently had a "Word for the Day" post about "tuo quoque"). Someone who's read enough of the Religion Forum--or even just this thread--can easily turn it against Protestants and others.