“Not Catholics.”
This has been hashed out many many times on these threads. The Roman edifice does indeed see itself as the one true church. Even the use of the word “Catholic” which is another word for the Body of Christ suggests it. The Body of Christ is made up of all Christians. The Vatican and those who follow and obey it are not Christian.
“Why was the expression...”
So you are posting Vatican catechisms to proclaim the Vatican is right? Here’s a novel thought, post Scripture.
“Some people are just doofusi. Speaking generally.”
If you are speaking about yourself I won’t argue with you as you know yourself better than I do, but don’t you think you are being a little harsh on yourself? Generally speaking of course.
No, it doesn't. Cite your source or admit the lie.