In Revelation 18:1-5, we find the following passage:
And after these things I saw another angel come down from heaven, having great power; and the earth was lightened with his glory.
2 And he cried mightily with a strong voice, saying, Babylon the great is fallen, is fallen, and is become the habitation of devils, and the hold of every foul spirit, and a cage of every unclean and hateful bird.
3 For all nations have drunk of the wine of the wrath of her fornication, and the kings of the earth have committed fornication with her, and the merchants of the earth are waxed rich through the abundance of her delicacies.
4 And I heard another voice from heaven, saying, -->.Come out of her, my people<<--, that ye be not partakers of her (Rome) sins, and that ye receive not of her plagues.
5 For her sins have reached unto heaven, and God hath remembered her iniquities."
God has His people, in all churches, or else He would not be calling them out of the apostate church. I understand the concept that you are addressing with the "Christians only" title, but do consider that many are under what their leaders are teaching them, especially RCC, and they feel that they are in the the church. Just a lil heads up. Not trying to debate or anything :-)