It would be wrong not to consider Shinotism a valid form of religion because it may not correspond to our preconceived ideas about what a religion should be. Judaism is ocnsidered a valid religion, although the Hebrew Bible demosntrates a patriotic perspective at least as great as the religious perspective.
Shinto is the indigenous religion of Japan. Like Hinduism, it is not credited to any particular founder. The Japanese gave their religious beliefs a name, in order to preserve the religion, while Buddhism & Confucianism were entering into their country.