Many Biblical scholars interpret the great whore of the Apocalypse to be a corrupt religious system, and I agree with this interpretation! However, some of these same scholars also say this corrupt religious system must be the Vatican, or Papal Rome, the Roman Catholic Church. Certainly, this was the point of view of at least some of the leaders of the Protestant Reformation. While any church can become corrupt, there is nothing keeping that same church from repenting and following the Lord. Nevertheless, the clear implication of the text is that the great whore must also be great Babylon of Revelation 16:19, whom the Lord judged, and is the same mentioned in Revelation 17:5. The text points to a corrupt religious system of the first century AD, not anything that arises later. Any attempt to make the great whore a corrupt religious system of the future, would be wrong and opposed to the simple reading of the text.
It seems that the very first thing to occur after the fall of Babylon the Great (Revelation 16:19-20) was that one of the seven angels, who had one the seven bowls of wrath, came to John to speak with him (Revelation 17:1). He told John to “Come” with him. This same Greek word is used by Jesus to tell the rich young ruler to “come follow me” (Luke 18:21-22). Here, the angel takes John to a place where he is able to see the judgment of the great whore, who sat upon many waters. So, the angel carried John away to a wilderness, where he was able to see the great whore or harlot riding on a seven headed beast (Revelation 17:3).
Reading the Apocalypse is somewhat like viewing a great many videos of certain key events that take place in history, except that to view a film, one remains seated, while the film changes from scene to scene or spliced together to play out the whole series of great events. Nevertheless, there is a difference with how this was done in the Apocalypse. Instead of a series of events spliced together on a reel of film, the book of Revelation points to certain key historical events, which almost seem to be caught in a kind of time warp, so that they must be repeated constantly, over and over and over again. In order to witness those events, which are played out in apocalyptic form, one must receive a heavenly invitation. That one is then brought to a place where one of many specific events is played out, and each one is interpreted to him by an angel or whoever is the heavenly guide.
One could say that reading the Apocalypse is like being reminded that the birth of Jesus is constantly played out for men in the constellation Virgo, or that the great spiritual battle between Jesus and his enemies is born out for us in the sign Draco in the constellation Sagittarius (Revelation 12:3). One could flip through the pages of the Apocalypse, until we come to chapter 15. There we are shown a sign within a sign, that is, seven stars (the big dipper) within the sign: Ursa Major. These seven stars, which we call the big dipper, contain a heavenly message that points to the “cup of the Lord’s indignation” (Revelation 15:1). These signs appear to us, as though they were caught in a time warp, constantly repeating their story from the heavens. There they repeat their record annually for all to see and understand. We may try to place our own interpretation upon them, even use them for corrupt purposes, but the heavens were laid out by God, himself, and he calls out every star or constellation by name (Psalm 147:4). He gives them their interpretation, and it is our responsibility to guard his word against corruption, because, left to ourselves, we don’t want the Lord to influence our lives (cp. Romans 1:28).