There is a lot of wiggle room in this statement created by the word knowing. Certainly if one was never exposed to the RC teachings, one could not know. If were exposed (as might be the case for a Muslim) they may still not know in the sense that they do not believe.
Does this Vatican II fuzzy statement supercede the previous black and white statements?
Pick the weakest statement, and attack syntax and grammar. Which of the previous infallible statements most closely parallels this statement?
Can't tell from your argument whose side you're taking.
I am not taking sides. I am trying to find out what the Catholic church currently teaches. I found a satisfactory answer at that web site I referred to in a previous message.