Not to be unduly challenging, but just reaching for clarity here: You say thee are "quite a few" Catholics in FR who say Protestants are not Christians. Could you find me one? Seriously.
I've honestly not seen it, but if you have, I want to swing into my self-appointed but hopefully constructive role of Mater et Magistra and Remedial Catechist Lady.
I don't know what your experience has been here at FR, but it's possible there may have been a misunderstanding of basic terms. Believing in a heresy (a religious error) or being in schism (formal church separation, esp. with bishops not in communion with each other) is not the same as being "non-Christian" or "damned."
I fully expect to see throngs of blessed souls rejoicing around the Throne of God who might have been involved in some degree of heresy or schism on this earth. As far as I can see (I speak here of my own observation), most heresy and schism stems from having been born and raised in a "separated" group and involves honest mistakes with no conscious choice against the Truth.
You have to be pretty "knowing" and "intentional" --- in other words, informed and deliberate --- to be culpable guilty of "formal heresy" especially in today's world, where confusion is so endemic.
Jesus is a just judge: so just, that when He makes His judgment, every single soul will say, "He's a genius: He's speaking exactly to my heart and my condition, and He got that absolutely right."
So Catholic doctrine explicitly teaches that a person in innocent error is not, for that reason, non-Christian or hated by God or damned.
I suppose there may be people who don't know that.
Judith Ann
This whole discussion has become another great example of goalpost moving.
Catholics regularly tell non-Catholics they are going to hell since they are heretics and have ex-=communicated themselves, which effectively damns them according to Catholic teaching.
Matter of fact, Catholic think it’s presumptuous for ANYONE to claim they are going to heaven.
Besides that point, Catholic teaching itself is replete with condemnation for people who don’t submit to Rome.
So finding a post where Catholics telling others they are not Christian might be tough, but they do tell them they are not saved cause they are not Catholic and don’t eat Jesus.
Does it "explicitly define" what innocent error is??