In a previous post I mentioned the stigma heavily associated with the term "atheism" in some countries, and how even some very outspoken atheists avoid calling themselves that, instead opting for the cop-out term "agnostic" (which is a category error, really.) I also mentioned the weird argument that some theists often throw that "you are not really an atheist."
In some countries (especially the United States, but also some other countries) the word "atheist" really does carry a lot of baggage with it. If you declare yourself to be an atheist, you are immediately assumed to hold a lot of other views as well.
In itself, "atheist" simply means "not theist", in other words, someone who has no belief in gods. There's nothing else that the word implies. You can believe all kinds of nonsense and still be an atheist. For example Buddhists are atheists (because they are not theists), and many UFO worshippers (such as Raelians) are also atheists. There exist many people who even believe in the paranormal and supernatural, yet are still atheists (because they don't have theistic beliefs.) Atheism in itself does not imply skepticism.
However, as said, in many countries "atheism" carries a lot baggage. If you are an "atheist" you are immediately assumed to also be a so-called strong atheist (ie. one who has the conviction that no gods exist), anti-religious, immoral, rational skeptic, secular humanist, believer in science and evolution, believer in the appearance of the Universe ex nihilo, believer in abiogenesis, pro-choice, liberal, feminist, and so on and so forth. That's quite a lot of baggage to carry. (Many outspoken atheists do fit many of those descriptions. However, that's not what the term "atheism" in itself implies.)
Many theists actually get quite dogmatic about it, if you try to discuss the real meaning of the term. Some of them go to ridiculous lengths to try to argue how the word "atheist" is the exact same thing as what's called "strong atheist", as well as implying many of those mentioned things. I have never quite understood why they are so dogmatic about it.
Which brings up to the subject of that weird argument that some theists use as some kind of "attack" against atheists when discussing with them, that if they show any kind of "weak atheism" (in the sense that they admit not knowing something for certain) they will vehemently claim something along the lines of "you are not an atheist."
For a long time it puzzled me why some theists pursue that notion so vehemently and why they think it's some kind of good counter-argument to anything. Even if we disregard for a moment the true meaning of the term, what does it matter if someone is or isn't a (strong) atheist? Shouldn't this person's arguments be what matters, not what we classify him or her?
One day a realized what the idea is: It's some kind of twisted notion that nobody can be a true atheist (ie. strong atheist) with good reasons. They are just pretending, and inventing all kinds of excuses. Deep inside they "know that God does exist, they just deny it."
The "logic" here is that since an atheist cannot be one for any good reason, the theist doesn't have to listen to those reasons either. They are just excuses that the self-proclaimed atheist invented, and thus can be ignored and rejected outright, without consideration. When the theist convinces himself and others of this, it predisposes them to not listen to any arguments that an atheist may present. It's a defense mechanism. This is closely related to the notion of "poisoning the well".