Because they forsook

Judges 2:12, 13
Thus they forsook the LORD, the God of their fathers, who had brought them out of the land of Egypt, and they followed after various gods of the people all around them. They bowed down to them and provoked the LORD to anger, . . .

Jeremiah 1:16
I will pronounce My judgments against them for all the evil they did, when they abandoned Me to burn incense to other gods and to worship the works of their own hands.

Lamentations 2:16, 17
All your enemies open their mouths against you. They hiss and gnash their teeth, saying, "We have swallowed her up. This is the day for which we have waited. We have lived to see it!" . . .

Lamentations 4:13-15
But this was for the sins of her prophets and the guilt of her priests, who shed the blood of the righteous in her midst. . . .

Ezekiel 14:23
They will bring you consolation when you see their conduct and actions, and you will know that it was not without cause that I have done all these things within it, declares the Lord GOD.'"

Ezekiel 36:17-20
"Son of man, when the people of Israel lived in their land, they defiled it by their own ways and deeds. Their behavior before Me was like the uncleanness of a woman in her monthly impurity. . . .

therefore

2 Chronicles 36:17
So He brought up against them the king of the Chaldeans, who put their choice young men to the sword in the sanctuary, sparing neither young men nor young women, neither elderly nor infirm. God gave them all into the hand of Nebuchadnezzar.

Daniel 9:12
You have carried out the words spoken against us and against our rulers by bringing upon us a great disaster. For under all of heaven, nothing has ever been done like what has been done to Jerusalem.