In Habakkuk 1:12b-13, at least the prophet is claiming that even fallen Israel is more righteous than Babylon (emphasis added):
O LORD, you have appointed them to execute judgment; O Rock, you have ordained them to punish. Your eyes are too pure to look on evil; you cannot tolerate wrong. Why then are you silent while the wicked swallow up those more righteous than themselves?
If one looks at the book of Daniel, one gets an impression of how righteous Nebuchadnezzar was not that long after the conquest of Judah. He is easily angered and prideful. When told by the astrologers that "No king, however great and mighty, has ever asked such a thing of any magician or enchanter or astrologer." (2:10b [NIV]), he was outraged to the point that he planned to execute all the wise men of Babylon. While one cannot judge an entire people by their leader, moral character tends to leak both ways (from the culture to the leaders and from the leaders to the culture).
If one looks at the book of Judges, one sees that God repeatedly hands over his chosen people to those who appear to be less righteous (and certainly less favored).
Psalm 78:34-38 seems noteworthy in this context:
Whenever God slew them, they would seek him; they eagerly turned to him again. They remembered that God was their Rock, that God Most High was their Redeemer. But then they would flatter him with their mouths, lying to him with their tongues; their hearts were not loyal to him, they were not faithful to his covenant. Yet he was merciful; he atoned for their iniquities and did not destroy them. Time after time he restrained his anger and did not stir up his full wrath.
While a passage like Jeremiah 2:11 (where Israel is not even as good at henetheism as other nations) may indicate that Israel was even more wicked than Babylon--and a strong case can be made that given the greater favor and greater revelation their unfaithfulness was more wicked (e.g., Hebrews 2:1-4--the dreadfulness of neglecting such salvation--or Isaiah 5:4--where God's special favor produced wild grapes and justice would be harsh--or even Matthew 23:33-39--where treatment of the prophets accumulates guilt)--, it seems that it is the Righteous One striking his people that is the kindness (cf. Psalm 141:5) and not that he is leading them into greener pastures.
If one again looks at the book of Daniel, one might see another reason for the exile: to reveal the truth to "that ruthless and impetuous people" (Habakkuk 1:6 [NIV]). As with Joseph in Egypt, the Babylonians were exposed to people of extraordinary integrity and to supernatural signs of favor because of the exile.
As with Jonah--and even at the time of Jesus with the money changers and animal sellers in the court of the Gentiles (rf. Matthew 21:12-13 where the most stinging portion of the quote from Isaiah 56:7 is left out, "house of prayer for all nations")--the people of God had forgotten that they were to be a light to the Gentiles, blessed to be a blessing to all peoples (Genesis 12:3). (E.g., the queen of Sheba was not meant to be drawn simply to praise the greatness Solomon but to see behind this the greatness and love of God [rf. 1 Kings 10:1, 9].)
