The list was a step-by-step guide to understanding the point, which once again I failed to make.
I'll try again.
You say religion is "a set of beliefs concerning the cause, nature, and purpose of the universe" and say that therefore atheists are religious.
The third part of your definition, the 'purpose" part, by definition cannot apply to atheists, and therefore your definition is wrong.
Purpose indicate a meaning an objective that a group of people have in regarding to something (deity, money, health, other...).
Atheists don't believe in God but they don't have a faith: so the word purpose has no meaning to them.
You know that. I know that. Try explaining that to BADecker.