DD:
Atheist, christian, buddhist, quaker, agnostic, etc. are labels that people take upon them. I think it is more prudent to give the labels the meaning the people who carry them want them to have, rather than the derogatory or logically unsound definition you want them to carry.
For example, i could say that being a christian is about believing in zombies because i believe Jesus and Lazerus was zombies, but it would not really seem very fair since very few christians mean that when they say "i am a christian".
In a similar vein, i have never seen an atheist say he is an atheist because he has some special argument that rule out a deity. Personally i would be very certain such an argument was false, and i would love to pick it apart. The sence most atheists are atheists are like Dawkins, who simply believe a given God should be evaluated like any scientific idea.