First definition of “Religion” listed on dictionary.com:

Religion: a set of beliefs concerning the cause, nature, and purpose of the universe, esp. when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs.

I think [b]all[/b] moral beliefs fit into this definition (especially if I try to cram them into the definition for the sake of strengthening my argument!)