Answer by Kris Rosvold:
Full disclosure: I am an atheist, and sometime agnostic, (small "a") and a Unitarian Universalist; who has been a Christian and "gave it up for Lent" at age 6 due to blatant contradictions between the teachings and the actions of the Church, and its leaders/members. I've also studied Islam, Buddhism, and a bit of Sufism while searching for a religion (fellowship) which fits for me. UU and non-theistic Buddhism are the two which even come close to a fit.
I do think it's an important distinction between arguing from a position of not believing in a deity vs. arguing from a position of no deities exist.
Here's the difference:
The first position: " I don't believe in deities." (or its theist opposite) says just that… That "I do not believe in deities…period." This position, logically, leads nowhere else. It is a simple statement that deities as a basis for my morals don't serve me, while it says nothing about whether they are of service, to you, in your life.
It is a statement of an agreement to disagree, and that this disagreement about what's appropriate and useful in each of our lives is perfectly OK.
It also says that "Such decisions SHOULD be left entirely to OUR individual determination, for our use in our individual lives, and families."
It is a core position of Respect for the Other.
The second position: "I don't believe that deities (could/do) exist." implies that you have no right to believe in deities because they appear nonsensical to the other person.
This position is just as disrespectful as the theistic zealot position of "You must believe or, at least, be required to act as if you do, because We believe." It is also based in the same false assertion of compliance which any zealot uses.
These latter two are both the opposite core assertions and are a direct position of Disrespect for the Other.
In effect, these latter two positions each say that "You are not competent to determine what is Right for your life and your family. Therefore We are going to determine that for you."
The first position, in the US is also supported by our core Law the US Constitution.
The second position is not supported in our core Law and in point of fact is specifically, and directly, banned from Law with a blanket prohibition.