It's not even a religious song. It's about a toy. In my school, we sung songs about Christmas that included lines like "Christ the Savior is born," or "Come and behold him, born the King of Angels... Christ the Lord." You never hear any songs for Hanukkah about God or Moses... come to think of it, apart from Adam Sandler, I can only think of two Hanukkah songs, and only one of them even mentions what Hanukkah is about. I can name and sing approximately fifty Christmas songs, maybe more.
Promoting religious tolerance is a lofty goal. Perhaps you need to attend some of your son's classes.