Jeremiah 51:47-49 says:
"Therefore look! the days are coming
When I will turn my attention to the graven images of Babylon.
All her land will be put to shame,
And all her slain will fall in her midst.
The heavens and the earth and everything in them
Will shout joyfully over Babylon,
For the destroyers will come to her out of the north,” declares Jehovah.
Not only did Babylon cause the slain of Israel to fall
But also at Babylon the slain ones of all the earth have fallen."
Jeremiah 51:60-64 says:
"Jeremiah wrote in one book all the calamity that would come upon Babylon, all these words written against Babylon. Furthermore, Jeremiah said to Se·raiʹah: “When you come to Babylon and see her, you must read aloud all these words. Then say, ‘O Jehovah, you have said against this place that it will be destroyed and left without an inhabitant, man or beast, and that she will become desolate forever.’ And when you finish reading this book, tie a stone to it and throw it into the middle of the Eu·phraʹtes. Then say, ‘This is how Babylon will sink down and never rise again because of the calamity that I am bringing on her; and they will grow weary.’"
Revelation is a vision given in signs. The rest of the scriptures in the Bible help us to understand what those signs mean. The book of Jeremiah talks a lot about Babylon and uses many of the same images as in Revelation.
"Yes, in her was found the blood of prophets and of holy ones and of all those who have been slaughtered on the earth." (Revelation 18:24)
If the empire of religious institutions was faithful, if she was doing her job, if religion was truly representing God, then she would have taught the people how to love instead of fomenting hatred, allowing abuse, teaching untruth, and encouraging division.
"God is Love."
God views the religious institutions as extremely bloodguilty. He doesn't approve of them and their heinous actions. He's going to take vengeance on the religious institutions for what they've done. That's what Revelation 18:24 is talking about.