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by the phrase " any system of beliefs" and based on your statement "I (and millions others) do not believe/worship/pray to a god/gods/superhuman/supernatural power.". By simply saying that (you do not believe in god = You believe that God did not exist). Therefore atheism is still a belief system....
Maybe or maybe not, but you have not proved it with your illogic.
There is no equality where you placed it.