Israel did have other Gods and so were ineligible for remarriage, but then there was the Cross! Their Creator/King/ex-husband was to be killed to regain them!
Deuteronomy 24:1-4
If a man marries a woman who becomes displeasing to him because he finds something indecent about her, and he writes her a certificate of divorce, gives it to her and sends her from his house, and if after she leaves his house she becomes the wife of another man, and her second husband dislikes her and writes her a certificate of divorce, gives it to her and sends her from his house, or if he dies, then her first husband, who divorced her, is not allowed to marry her again after she has been defiled. That would be detestable in the eyes of the LORD. Do not bring sin upon the land the LORD your God is giving you as an inheritance.
God calls remarriage to a woman that you have divorced, who has had a second husband, detestable.
There is something far different goo g on here.
Unless Israel herself dies she cannot be fit for Him.
As the apostle wrote, we, a people who were never a people to begin with, taken from all nations and peoples, not taken just from the children of Jacob, are pledged a vigin bride. Not a divorced and adulterous one taken back in her filthiness.