Show me one official Church document that says ROMAN Catholic Church. The modifer "Roman" is simply because the chief administrative center happens to be in Rome. I doubt it will always be there, and in the event that it is moved, the modifer "Roman" will die out. You appear to be focusing on a very minor peripheral and making a mountain out of it.
Christ had designed to conquer by purely spiritual and moral means. Conversion was voluntary, a genuine change in heart and life.
But now the military spirit of imperial Rome had entered the church. The church had conquered the Roman empire. But in reality the Roman empire had conquered the church, by making the church over into the image of the Roman empire.
The church had changed its nature, had become a political organization in the spirit and pattern of imperial Rome.
The imperial church of the 4th and 5th centuries had became an entirely different institution from the church of the first three centuries. In its ambition to rule it lost the Spirit of Christ.
Worship, at first very simple, was developed into elaborate, stately, imposing ceremonies having all the outward splendor that belonged to Rome.
The church became an amalgamation of pagan philosophies. The church lost sight of its true mission.
they are Roman because their headquarters is in Rome...the Dodgers used to be the Brooklyn Dodgers, they are now the L.A. Dodgers, The Milwaukee Braves are now the Atlanta Braves....actuaally, all three are the Catholics, the Dodgers, and the Braves....wherever they're from or headquartered.