Paul wrote ABOUT the Catholic Church, not TO the Catholic Church. Starting with this: 2 Cor. warning that there are "many which corrupt the Word of God." He wrote many things about the Catholic Church, but one of my favorite is: well, I can't choose a favorite, They are ALL favorite warnings against false teachers, deceivers, another Jesus, another gospel, another spirit, another doctrine, etc.
Paul writing to the Catholic Church...lol!