They’re not quite addressing the same issue.
I’m simply denying the existence any widespread evangelical/Protestant dogma that says that it’s impossible for a Roman Catholic to be a Christian. The person you pointed out claimed that being a Roman Catholic does not guarantee being a Christian. That’s a different assertion.
The evangelical creed is almost always that being a Christian depends on whether you put your faith in Jesus Christ for your salvation, with fiddly details about destiny, choice, timing, and consistency over time that I don’t intend to get into which involve what is called the Arminian/Calvinist debate. I try to avoid that debate. (Incidentally, almost all agree that if no works based in faith are produced, no salvation occurred.)
Ah, yes, then I agree with you that there is no “widespread” dogma. I understand that you were asking if there were no individuals who said that — unfortunately there are many on FR (their numbers in the real world seem minuscule) who call us as damned. Unfortunately the rest of the non-Catholic crowd doesn’t haul these guys up, so most of us get the erroneous impression that ALL of you guys think that way...