[ ri-lij-uh n ]
noun
1. a set of beliefs concerning the cause, nature, and purpose of the universe, especially 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.
2. a specific fundamental set of beliefs and practices generally agreed upon by a number of persons or sects: the Christian religion; the Buddhist religion.
3. the body of persons adhering to a particular set of beliefs and practices: a world council of religions.
4. the life or state of a monk, nun, etc.: to enter religion.
5. the practice of religious beliefs; ritual observance of faith.
6. something one believes in and follows devotedly; a point or matter of ethics or conscience: to make a religion of fighting prejudice.
religions, Archaic .
7. religious rites: painted priests performing religions deep into the night.
Archaic .
8. strict faithfulness; devotion: a religion to one's vow.
Notice that most of the definition have nothing to do with a supreme being... at least not directly. So, as usual, you have been proven wrong. Besides, what does this have to do with the idea of keeping quiet about your religious stuff? You certainly aren't keeping quiet about YOUR religious beliefs.
1. Not believing in silly science fiction books isn't about being concerned with what caused the universe and is also not a set of beliefs either.
2. Not believing in gods is not a set of beliefs, it's simply not accepting shit without evidence.
3. Same as 2
4...
5. same as 2
6. I don't believe it, I know it for a fact since evidence points towards it, your god doesn't exist as suggested by science, I also don't follow it devotedly, there is nothing to follow, I simply don't believe in it.
7. and 8. useless
Again, not believing in gods is not a religion proven by definition.