I think any valid counter-argument would apply universally to the same, or variations of the same, position whoever held to them.
And there is another more complex reason.
The great logician and teacher of Wittgenstein, Friedrich Ludwig Gottlob Frege (b. 1848, d. 1925), said that it is “necessary to distinguish a proposition from its sense, thus opening up the possibility that two propositions could have the same sense and yet differ in the ideas associated with them.” Wittgenstein wrote that "The actual sense of a proposition is the same for everybody; but the ideas which a person associates with the proposition belong to him alone...No one can have another’s ideas.” I think propositions using the term “atheism” are a good case of this distinction. It is clear that “atheism” has ideas associated to it that are different than mine, yours, Zenzoe, and CeciAtea.
Interesting point from the Frege link:
"To ground his views about the relationship of logic and mathematics, Frege conceived a comprehensive philosophy of language that many philosophers still find insightful. However, his lifelong project, of showing that mathematics was reducible to logic, was not successful."
Reminds me of Einstein's quest for the Unified Field Theory. If someone devotes the better part of their life pursuing something that they never quite achieve, are they a failure? The only failure is not trying at all, right?
This proposition related to atheism is drastically altered by our various individual ideas we bring to the table.