If Mystery Babylon is Jersualem how come Jerusalem is responsible for the blood of the martyrs of Jesus in Verse 6? Where are all the dead Christian martyrs killed by Jerusalem?
Well, let's see here, starting with the stoning of Stephen in Acts 7:
{59} They went on stoning Stephen as he called on the Lord and said, "Lord Jesus, receive my spirit!" {60} Then falling on his knees, he cried out with a loud voice, "Lord, do not hold this sin against them!" Having said this, he fell asleep. Acts 7:59-60 (NASB)
Which led to a great persecution against Christ's followers in Acts 8:
{1} Saul was in hearty agreement with putting him to death. And on that day a great persecution began against the church in Jerusalem, and they were all scattered throughout the regions of Judea and Samaria, except the apostles. {2} Some devout men buried Stephen, and made loud lamentation over him. {3} But Saul began ravaging the church, entering house after house, and dragging off men and women, he would put them in prison. Acts 8:1-3 (NASB)
Which led to the deaths of thousands of believers who were first persecuted by the Jews. And here's a bedtime story for you from Eusebius on the death of the Lord's brother James:
Now follows a more full account of the death of James the Just, (coll. p. 49, 77,) the first bishop of Jerusalem...
As there were many therefore of the rulers that believed [in Christ], there arose a tumult among the Jews, Scribes, and Pharisees, saying that there was danger, that the people would now expect Jesus as the Messiah. They came therefore together, and said to James,
"We entreat thee, restrain the people, who are led astray after Jesus, as if he were the Christ. We entreat thee to persuade all that are coming to the feast of the passover rightly concerning Jesus; for we all have confidence in thee, for we and all the people bear thee testimony that thou art just, and thou respectest not persons. Persuade therefore the people not to be led astray by Jesus, for we and all the people have great confidence in thee. Stand therefore upon a wing of the temple, that thou mayest be conspicuous on high, and thy words may be easily heard by all the people; for all the tribes have come together on account of the passover, with some of the Gentiles also.
The aforesaid Scribes and Pharisees, therefore, placed James upon a wing of the temple, and cried out to him, '0 thou just man, whom we ought all to believe, since the people are led astray after Jesus that was crucified, declare to us what is the door to Jesus that was crucified.' And he answered with a loud voice, 'Why do ye ask me respecting Jesus the Son of Man? He is now sitting in the heavens, on the right hand of great Power, and is about to come on the clouds of heaven.'
And as many were confirmed, and gloried in this testimony of James, and said, Hosanna to the son of David, these same priests and Pharisees said to one another, 'We have done badly in affording such testimony to Jesus, but let us go up and cast him down, that they may dread to believe in him.'
And they cried out, 'Oh, oh, Justus himself is deceived,' and they fulfilled that which is written in Isaiah, 'Let us take away the just, because he is offensive to us; wherefore they shall eat the fruit of their doings.'
Isa. 3.
Going up therefore,
they cast down the just man, saying to one another, 'Let us stone James the Just' And they began to stone him, as he did not die immediately when cast down; but turning round, he knelt down saying, 'I entreat thee, 0 Lord God and Father, forgive them, for they know not what they do.' Thus they were stoning him, when one of the priests of the sons of Rechab, a son of the Rechabites, spoken of by Jeremiah the prophet, cried out saying, 'Cease, what are you doing? Justus is praying for you.'
And one of them, a fuller, beat out the brains of Justus with the club that he used to beat out clothes. Thus he suffered martyrdom, and they buried him on the spot where his tombstone is still remaining, by the temple. He became a faithful witness, both to the Jews and Greeks, that Jesus is the Christ.
Immediately after this, Vespasian invaded and took Judea."
Eusebius Pamphilus,
The Ecclesiastical History of Eusebius Pamphilus, WORD
search CROSS e-book, 75-78.
{9} When the Lamb broke the fifth seal,
I saw underneath the altar the souls of those who had been slain because of the word of God, and because of the testimony which they had maintained; {10} and they cried out with a loud voice, saying, "How long, O Lord, holy and true, will You refrain from judging and avenging our blood on those who dwell on the earth? [lit. the land]" {11} And there was given to each of them a white robe; and they were told that they should rest for a little while longer,
until the number of their fellow servants and their brethren who were to be killed even as they had been, would be completed also. Revelation 6:9-11 (NASB)
{6} And I saw the woman drunk with the blood of the saints [holy Jews], and with the blood of the witnesses of Jesus [followers of Christ]. When I saw her, I wondered greatly.
Revelation 17:6 (NASB)
James the Just, was the last martyr killed in Jerusalem - like those before him - immediately before the Romans invaded Judea and Jerusalem.
Rome was the beast upon which Mystery Babylon rode. Mystery Babylon was Jerusalem.
Hope this helps.
They, in effect, prostituted themselves and made themselves the subject of God's wrath.