Some people do not feel that atheists and/or non-theists need a symbol. After all, why wear a button that says, “I don’t collect stamps.” But atheism isn’t about disbelief. Sure, the term atheist necessarily implies that they do not believe in gods, but that is not what being atheist is about. Atheists don’t sit around and un-pray to nothing. When they get together they don’t talk about how much they don’t believe in things. In fact, they’re often talking about the things they do believe in; things like science, art, and beauty.

Atheism isn’t a religion.

That’s true. However, contrary to popular opinion, atheism is a belief system. It is not a half-hearted lack of belief in gods; atheists actively believe that there are no gods.

Atheists don’t need a symbol.

Sure they do. Symbols are just a super-efficient form of communication. You don’t have to wear a symbol on your shirt, on your skin, or on your car. The symbol can just mean something to you. But if you do want to show off your beliefs (as humans are often wont to do), then selecting a universally-accepted symbol is a good way to go about doing it. The question is: What do you want to communicate?