"Roman" Catholic as a blanket term for all Catholics was first used as an insult by the Anglicans in the 16th century. They wanted to distinguish themselves from Rome and keep the name "Catholic".
There are 23 rites and Roman or Latin is just one of them, although it is the largest by population. Latin rite is the same thing as Roman rite. The popular "RCC" notation implies the other 22 rites disappeared and it is inaccurate, not to mention annoying. "CC" is much better. The Melkite Catholics in Syria were the ones being beheaded (among others) by the ISIS, but they are not "Roman Catholics'.
When the apostles brought the Gospel to the major cultural centers of their day the essential elements of religious practice were inculturated into those cultures. This means that the essential elements were clothed in the symbols and trappings of the particular people, so that the rituals conveyed the desired spiritual meaning to that culture. In this way the Church becomes
all things to all men that some might be saved (1 Cor. 9:22).
Catholic Rites and Churches
The Pope never uses the phrase, unless he is addressing the Catholics in the diocese of Rome, where he functions as a local bishop.
"Roman Catholic" is said to be mentioned in only 2 places in the catechism, but I haven't found it, and I never use the term. I am Catholic. Period. Who happens to be in the Roman or Latin rite by virtue of geography. I can participate in any rite because "Catholic" means universal.
The bottom line is Catholics don't get into scrupulous details over "Roman" Catholic because it is generally accepted. (except me) Most of North America is of the Roman (Latin) rite.