Because Mom and Dad had sex ....

At first, I identified as agnostic for these very reasons that are listed in this article. Then I ran across a quiz where it would to help you tell the difference between agnostic and atheist. After answering the quiz questions it said I was an atheist. So I guess I'm an atheist

Because religion exists.

It depends upon what meaning you are giving to 'atheist'. To my way of thinking, the word simply means one who has no belief in god(s). This can be equated to a number of different things. There are people in the world who do not believe in the kraken. Here there is considerable room to question why someone would not believe in the kraken because there is considerably more evidence that something like the kraken could actually exist in the natural world. As for god(s), there is none at all. It is far easier to understand why someone would not believe in god(s) as opposed to not believing in kraken.

So, why do atheists exist? Many of them, such as myself, have no reason to believe in god(s), but have ample reasons for not maintaining such a belief.

because there are so many religious people

Atheist exist because God believes in us .

We can be gnostic atheists when it comes to specific gods. There is conclusive evidence the God of Abraham cannot exist, for instance. Since Moses and the Exodus are known fiction, there is no need to waste time considering that story further.

The only god worth remaining agnostic about would be a deist god, unlike anything from any existing alleged revelations.

Because I do. Deal with it!

We think therefore we are.

As I have pointed out before, th graph is wrong in its definitions. Gnostic relates to a mystical knowledge. And atheist does not believe in a god or gods (or the supernatural). One cannot be a Gnostic Atheist by definition.

Because God dosn't.