A religion doesn't have to be about a supreme being does it? Couldn't it just be a "moral standard" among those in the religion? I mean, do you remember that guy Jesus... who said to follow you're heart. Religion (Such as christianity for example) relates to the heart, but not anymore... now it's about who's religion is right. While really they are all right.
Some relate to the mind, though... and some relate to the soul. (Hinduism, I believe) But that is a different issue.