For me, this is all just a social game, semantic trickery, that is hard to have sympathy for, but I can't honestly criticize nonbelievers who want to avoid the social stigma falsely attached to a maligned word. Prejudice in this country, in some places and situations, is certainly real and harmful enough to justify a desire to dodge it. If black people could pretend to be white, I'm sure some of them would. This is frequently enough true for gays that they have a whole terminology of social disguise (like "in the closet" and "beard"). You can't condemn this until you've walked a mile in their shoes.
There is also a silly and heated debate (even so far as to cultivate outright rage) between atheists and agnostics as to who is really what. Of course, these terms don't even have a single meaning. Just as "atheist" can mean "denier" or "unbeliever" (generating the rather lame, confusing, and misleading terminological distinctions of "hard" and "soft" atheist or "positive" and "negative" atheist), so can agnostic mean "undecided" or "dunno!" The latter is more etymologically and historically correct, since agnosticism is supposed to be the formal position that one cannot know whether God exists or not (whether by definition or as a contingent fact of a particular agnostic's limited access to relevant evidence), but the former meaning is still very common in actual use, and both have crept into other contexts (so, for example, you can be an "agnostic" now, in either sense of the term, as to whether Robin Hood actually existed).
I say more about all this in Sense and Goodness without God (see pp. 253-56). Beyond what I say there, technically I would prefer "undecideds" to call themselves anapophasists (the actual Greek for "without a decision"), so agnostics can be identified as those who formally claim not to know (since a-gnostikos means "without knowledge"), but you can probably see how these overlap a great deal. The line between them is certainly blurry. And at any rate, I have no illusions about my prospects for changing linguistic convention. My prospects are better in the other direction, since I prefer "atheism" to be used in its equally literal sense: a-theismos, without theism, i.e. without a belief in god. For in actual practice, this is how it is almost always used. And, as far as I see it, any other usage rhetorically violates the Law of the Excluded Middle.
Some theists, however, who are often fond of playing word games, have tried to act the linguistic imperialist and insist (contrary to any etymological or historical or philosophical precedent) that "atheism" means only the positive denial of every god's existence. In my opinion that's just verbal thuggery, since it does not agree with English usage or actual fact and is basically a "special" definition invented solely for polemical purposes, not for any authentic aim, like knowledge or practical application.
But even some atheists (or, I should say, "nonbelievers") jump into this fray, usually with "agnostics" accusing "atheists" of playing verbal games when they deny this religiously contrived definition of "atheism," or with atheists accusing agnostics of accepting it. It gets even crazier when either side starts rambling on about babies being either "atheists" or "agnostics" because they've never even heard of God and certainly have no "belief" in one, and eventually fictional cultures get invented where no one has ever heard of or thought up any notion of any god. No one seems to notice (or care) that examples like these constitute a kind of category fallacy, since there is a mountain of difference between someone who has a belief-state (of either belief or disbelief in some proposition) and someone who has no corresponding belief-state at all. You might as well argue that stones and trees are atheists. Sure, in a sense that's true, but why should anyone care?
This merry-go-round isn't very common. The whole tussle is limited to a rather small segment of nut-headed youths and grumpy old men within the atheist community. But it's all so silly that I find the whole "who really is an atheist?" debate rather pointless. In actual fact, every unbeliever is both an atheist who denies God and an atheist who merely doesn't believe in God. So there is no sense in which anyone can just pick one and deny they are the other. Shocking thing to claim, you say? Well, it can be demonstrated quite easily.
Let's invent two gods, extreme cases each, but you should be able to see how all other gods fall on a continuum between them:
Bumpypoo is a supremely powerful God, creator of the universe, who uses his powers to make sure you never have any reason to believe he exists.Can you deny the existence of Bumpypoo? Or do you merely lack belief in him? Assuming there is a difference, you can only assert the latter. Because you can never, even in principle, have any evidence against Bumpypoo's existence. By definition he will ensure that the evidence always misleads you, therefore evidence of his absence is not at all predictive of his non-existence. This is true even for a devout Christian: it is logically impossible for you to deny the existence of Bumpypoo. You can only disbelieve in his existence. This constitutes what I call a "Cartesian Demon" in Sense and Goodness without God, so to learn more about that you can check the index there. But my point here is, everyone is an agnostic with regard to Bumpypoo. They haven't any choice.
Okay. Now consider this:
Monkeybutt is a supremely powerful God, creator of the universe, who uses his powers to make sure you have tons of clear and undeniable evidence that he exists.Can anyone say they don't outright deny the existence of Monkeybutt? It would be patently irrational to say you "merely" don't believe in Monkeybutt, because you would have the vast evidence of your own direct experience against the existence of Monkeybutt. The absence of evidence in this case is not only highly predictive of his non-existence, it virtually entails his non-existence. Hence you can be as certain of his non-existence as of anything you claim to know about anything.
Therefore, everyone is a soft/negative atheist vis-a-vis Bumpypoo and at the same time a hard/positive atheist vis-a-vis Monkeybutt. Therefore, there is never any real separation between an atheist and a formal agnostic. Any atheist who denies one god's existence will also be an atheist who merely doesn't believe in some other god's existence, and vice versa, since everyone, always, does both. Ergo, no agnostic can ever claim they are not an atheist and no atheist can ever claim they are not an agnostic. Bumpypoo and Monkeybutt dash any hopes atheists or agnostics might have had of avoiding each other's label.
Of course, even Christians are, in a limited sense, atheists of both types, with regard to Bumpypoo and Monkeybutt (and thus agnostics with regard to Bumpypoo). So the only thing that separates believers in God from the rest of us is a belief in at least one god. Ergo, the only thing that can ever logically matter in distinguishing theists from "atheists" is whether we believe any god exists. Hence all that matters in defining an atheist is that an atheist does not believe in any god. Whether there are some gods atheists also deny is wholly irrelevant--because there are some gods everyone denies, even believers! And as long as we don't believe in any God, we are not theists, and are therefore atheists. Unless you want to invent some new stupid word. But until you invent a mind-altering machine that can insert this new word into the brains of billions of people, your new word won't be of any popular use. Indeed, even if you could accomplish such a thing, I doubt your stupid new word would even be useful.
At most you can bicker about "which" gods certain atheists deny and which ones they merely disbelieve (again, assuming you can actually identify a difference). But how can that ever matter for whether you are an atheist or a theist? Even if Atheist A disagrees with Atheist B as to which gods can be denied and which merely disbelieved, it remains the case that the only thing distinguishing both Atheist A and Atheist B from all theists is that neither A nor B believes in any gods. Otherwise, both A and B deny some gods and both A and B merely disbelieve in some gods, and since we have no terminology in the English language to distinguish Atheist A from Atheist B (or from atheists C, D, E, etc., ad infinitum), there is no sense in trying to deny that A or B is "really" an atheist, or trying to claim A or B is "really" an agnostic, or really "not" an agnostic, or debating whether it's Atheist A or Atheist B who's the hard or soft atheist. They are always both. Because of Monkeybutt and Bumpypoo, they're all of the above.
Therefore, there is simply no such thing as a "soft atheist" who is not also a "hard atheist," or a "hard atheist" who is not also a "soft atheist." If you don't believe in any god, then you will always be both. The only difference will be which gods you put where. Hence all unbelievers are both atheists and agnostics, and neither can deny either name. They can never be separated. Though these categories aren't synonymous, you still can't sort unbelievers into "atheists" and "agnostics" any more than you can sort them into "persons" and "people." Thus it is simply stupid to debate which you are.
Sorry, but I have to call it like I see it.
Update: When you apply Bayesian reasoning to the question, all this becomes even clearer. Just ask yourself of any god, "What is the probability that that god exists?" If the answer for any god is 50% or less, you are an atheist. If the answer for any god is above 50%, you are a theist. Although a very doubting one, if you assign nothing more than a 51% probability to any god; just as you'd be a very weak atheist if there is any god you honestly believe might have a 49% chance of existing, since that's as likely as the next baby being born a girl...which happens all the time, so it's not that unlikely. That's closer to anapophasy.