The difficult part is trying to decide what applies to all atheists.
Euh, no - that's the easy part.
There is one thing that ALL atheists have in common. No matter who they are or what their worldview is.
They
ALL answer "no" to the question "do you believe god(s) exist(s)?".
Some atheists will go further and claim / believe that
no gods exist.
But that is a separate claim.
It's like in court.
The accused is ruled either "guilty" or "not guilty". They accused is not ruled "innocent".
When someone is ruled "not guilty", then that does NOT mean they all believe the accused is "innocent".
It
just means that the case being brought forward was found insufficient to establish guilt.
I rule god to be "not guilty" of existing.
But if other atheists start saying things like "There is no God", they start to risk having the burden of proof.
Off course. That's a claim and it has a burden of proof. And certainly there are atheists that make that claim.
But that claim doesn't define their atheism. What defines their atheism is their disbelief of theistic claims. That is the common denominator among ALL atheists.
Though probably quite a few meant to say, "I don't believe there is a God." and misspoke.
I think the confusion arises from the practical implications of not believing the claim that a god exists.
Because for all practical intents and purposes, that would result in you living your life
as if no gods exist.
So people, theists in particular, consider that as "evidence" that atheists "believe" no gods exist.
It's a subtle, yet important, difference. A difference that theists tend to understand when it comes to
any other subject.
When the accused in court is ruled "not guilty", then he is set free. For all practical intents and purposes, he is treated
as if he is innocent. But he wasn't ruled to be "innocent". Instead, the conclusion of the case was
just "there is insufficient evidence to give a guilty verdict". So you treat the situation
as if he isn't guilty.
As if he is innocent. This, however, was NOT established.
Is he actually innocent? We don't know. All we can say is that there's insufficient evidence to consider him guilty.
So people are
assumed innocent until
shown to be guilty.
The same goes for the existence of gods (or anything else, for that matter).
Non-existence of entities is
assumed until existence has been demonstrated.
This is why we tend to say that atheism is the
default position.
Because existence needs to be demonstrated and if that fails, non-existence is
assumed. Which is not the same as
believed.