The Books of Maccabees are not included in the Hebrew Bible, which is the basis for the Old Testament in Protestant Bibles. However, they are part of the Catholic and Orthodox Old Testament. The primary reason for their exclusion from the Hebrew Bible is that they were written after the period considered authoritative by Jewish tradition.
Jewish tradition holds that the age of prophecy ended around 400 BCE, and the Books of Maccabees, which describe events from the 2nd century BCE, were written after this period. As a result, they were not included in the Hebrew canon. The Protestant Reformation later adopted the Hebrew canon, leading to the exclusion of the Books of Maccabees from Protestant Bibles.
In contrast, the Catholic and Orthodox Churches include the Books of Maccabees in their Old Testament because they use the Septuagint, a Greek translation of the Hebrew Scriptures that includes additional books not found in the Hebrew Bible. These books are considered deuterocanonical by Catholics and anagignoskomena by Orthodox Christians.
In summary, the Books of Maccabees are not in the Hebrew Bible because they were written after the period considered authoritative by Jewish tradition. They are included in the Catholic and Orthodox Old Testament because these traditions use the Septuagint, which includes additional books.