The absence of Christmas observance within Judaism stems from fundamental differences in religious belief. Christmas, a Christian holiday, commemorates the birth of Jesus Christ and celebrates his role as the Messiah. Jewish theology does not recognize Jesus as the Messiah, and therefore, celebrating his birth is incongruent with Jewish doctrine and practice. Observance of Christmas would be considered a violation of core tenets of the Jewish faith.
Jewish holidays are rooted in the history and experiences of the Jewish people, as chronicled in the Hebrew Bible (Tanakh) and interpreted through rabbinic tradition. These holidays, such as Passover, Rosh Hashanah, and Yom Kippur, commemorate events like the Exodus from Egypt, the Jewish New Year, and the Day of Atonement. Integrating a religious holiday from another faith would represent a departure from the unique historical and theological foundations of Judaism. Furthermore, some Christmas traditions, while seemingly secular, have origins and connotations tied to Christian beliefs that are incompatible with Jewish perspectives.