What does 1 Chronicles 9:1 mean?

All the people of Israel were listed in family records, which were written down in the Book of the Kings of Israel. But the people of Judah were taken away to Babylon because they were unfaithful. 1 Chronicles 9:1 - Modern Text Bible

(This verse explains that Israel kept careful records of their families, but Judah was exiled to Babylon because they turned away from God.)