Why were Deuterocanonical books rejected in the Reformation?

The *Deuterocanonical books* were included in the Septuagint, but not the Hebrew Bible. They are mostly included in the Catholic Old Testament, but not in the Protestant one. I understand the choice was made by Luther, who called the deuterocanonical books > Apocrypha, that are books which are not considered equal to the Holy Scriptures, but are useful and good to read Why weren't the deuterocanonical books considered equal to the Holy Scriptures?