Yes, I meant vacuous as in an empty proposition, not a comment on anyone’s competence or intelligence!
Well contrast “I do not hold a belief that X is true” with “I do not know whether X is true”.
I’d reason that a person stating the former is - epistemologically - no different to the latter, which one could refer to as agnosticism, at least informally.
If I do not know whether God exists then obviously I do not hold a belief, so why not simply say “I don’t know” and avoid all this lofty “atheism” talk?
I don’t agree that there is a default position either, at least not in any absolute, universal sense. One’s default position largely reflects one prior assumptions and there are no absolute, universal assumptions.
An atheist might as well say “Based on the assumptions I have made about the universe, I do not have a belief in God”, that is to say state those assumptions rather than a conclusion drawn from them.
Different assumptions lead to different worldviews.