I endorse this sentiment, although I do not think that you are following it objectively in this particular case. We do not base the label "atheist" on whether someone lacks a belief in gods. Rather we base it on whether they reject belief in gods.
Look at it from a logical perspective. If atheism were equivalent to lack of belief, then it would be entirely consistent to label someone an atheist who lacked belief in the statement "No gods exist." That is, the following statements would be logically consistent for the "atheist" X:
1) X does not believe that God exists.
2) X does not believe that God does not exist.
However, I doubt very much that anyone would reasonably hold that (2) describes the mental state of any atheist. Now, that said, I do not doubt that some, if not most, atheists in this thread will remain unreasonable about it.