I was raised Catholic. I made it all the way to my communion, and so I understand why people are drawn to religion. When things are hard it's easier to say things are out of your hands and in God's hands, but religion requires that you don't question it. You can't question any part of it because you'll quickly realize it doesn't make any sense. And so to summarize it in a short statement: I prefer the hard truth to a comforting lie.

'Why' can mean different thing. My justification for not being a believer is that there is no evidence of a god and there are sufficiently good explanations for how the world works.
But why did I come to believe this? I guess because I wasn't indoctrinated as a child and always wanted to know what was the truth. Education in the sciences also helped.

I’ve found not other choice ~

Honesty. Why pretend to believe something you don't know?

To paraphrase Matt Dillahunty, I don't have any evidence of a god, and until I get some, I just don't know.

Hi. I never believed in any god and do not see any reason to do so. I am not sure what it would take to change my mind but it would have to be beyond doubt in its authenticity. Something that could stand up to the scientific method would be a start.

Praying has gotten me exactly as much as birthday candle wishes, falling "srar" wishes, wishbone wishes, etc.

Prayers, much like worry and rocking chairs, give you something to do but it doesn't get you anywhere.

Many family members growing up were not very good or stable people, and their religious beliefs seemed to be intertwined with their immoral views and acts, and unstable personalities. Later, in college, I took a great books class. We read parts of the bible. A professor in that class was Calvinist, and I used the Socratic method on his views to try to figure some things out. I asked him if evil was defined as dysfunction, disease, destruction, etc. He said yes. So I asked if Satan was evil. Yes. Absolutely evil? Yes. Wouldn't that mean Satan was absolutely dysfunctional, diseased, destroyed, etc., and wouldn't that mean he didn't (indeed couldn't) exist? No, he told me. "One being can be absolutely evil, and that being is Satan." Ok, (I accepted that for the sake of argument), well, if that is the case, then Satan is absolutely evil and god is absolutely good, in which case they would be in an eternal stalemate.

Yes, he told me, until God throws Satan in the Lake of Fire at the end of time.

Ding. I felt a shift, a click...something. And I was an atheist. It was so absurd that I couldn't even accept it for the sake of argument. It was a bridge too far, and I couldn't accept any of the nonsense for the sake of argument again. It's just...literally...stupid. Nonsensical.

Still never saw a theist don't lie
and.....

Lack of ANY credible evidence, facts or data.
Some good credible evidence for me would be for god to separate the waters of the lake I live by and I could walk across on the lake bottom and back to prove that I am not hallucinating. Something it has supposedly done before on a much larger scale so shouldn't be asking too much.

Because I think, therefore....

Why do I not believe in the faith (belief without evidence) assertion that has no testable scientific evidence to suggest a god exists? Because there is no testable evidence to demonstrate a god exists.

You appear to not fully understand the definition of agnostic. Agnostic is questioning our knowledge (not belief) in a god. They are different.

Theist and Atheist are positions of belief. You can be an agnostic (realizes you can not know that there is a god) theist. Or you can be an agnostic atheist (not a theist).

I have studied the Bible enough to know that it is full of contradictions and false prophecies. If there were a god, would she really claim the Bible to be her word? I have asked many Christians for evidence that the Bible is true and that gods really exist. They have been unable to provide me with any solid evidence at all. Their apologetics are weak and full of holes. The Christian mythology is just as fictitious as the ancient Egyptian, Greek, Norse, Roman and other mythologies.

To get to the other side.

Solid. The likeliness we get confirmation of either is as close to 0 as you can get.