I think this is a pretty ridiculous assertion overall, but it’s still interesting.
To put it crudely, if Christianity is a fantasy religion, then Judaism is a science fiction religion. If the former is individualistic, magical, and salvationist, the latter is collective, technical, and this-worldly. Judaism’s divine drama is connected with a specific people in a specific place within a specific history. Its halakhic core is not, I think, convincingly represented in fantasy allegory. In its rabbinic elaboration, even the messianic idea is shorn of its mythic and apocalyptic potential. Whereas fantasy grows naturally out of Christian soil, Judaism’s more adamant separation from myth and magic render classic elements of the fantasy genre undeveloped or suspect in the Jewish imaginative tradition.