1. Where are you pulling this from? I'm just talking about what it means in a religious debate. Its actually pretty standard stuff if you pick up a philosophy of religion textbook or any academic book dealing with the subject.
2. It really just seems to me that with these definitions, someone is trying to swell the ranks of atheists. I mean people who do not believe in a God are now atheists? That's a standard statement for an agnostic....not an atheists. The agnostic says, "I do not believe God exists, but I also don't believe God does not exists." It seems like your defining atheism way too broadly, and the definitions themselves are very misleading. For example,
"Agnostic Atheist - A person who does not believe in the existance of a deity, OR --more specifically-- believes in the inexistance of a deity, but accepts that they cannot know for certain."
3. The two bolded sections are two completely different claims that are being used to define the same term......which should not be done with any definition. The first claim is compatible with someone also saying, "I do not believe in the nonexistence of a deity." For someone making the second claim, they could not then say "I believe in the existence of a deity" without contradicting themselves.In fact, all these definition are doing is using agnosticism as a synonym for skepticism, which is unneeded given that we already have the word skepticism.
http://plato.stanford.edu/entries/atheism-agnosticism/-a quick read on the subject. I will admit that the definitions are kind of arbitrary, but they are there for a reason....primarily to make discussion easier. The definitions you provided really just serve to complicate things for no reason at all.
1.You've already agreed that you searched and found some conflicting definitions so I don't think I need to search for anymore.
2. Yes, atheism is broad. It's simply a lack of belief. When you focus on atheists who believe God doesn't exist, then you're focusing on a specific group within athiesm. This group is called explicit atheists. Either way, you must recognize that they are a specific group, not all atheists. You can read it here:
3. Yes, they are different. As stated above, there are exclicit atheists to define the latter, while there are implicit atheists to define the former. Here, if you want I'll break it down even further.
- Gnostic Theist - A person who thinks there is enough information to know that at least one deity exists.
- Agnostic Theist - A person who believes that at least one deity exists, but accepts that thre isn't enough information to know.
- Agnostic Atheist - A person who does not believe in a deity, but accepts that there isn't enough information to know.
- Explicit Atheist - A person who believes in the inexistance of a deity, but accepts that there isn't enough information to know.
- Gnostic Atheist - A person who thinks there is enough information to know that no deity exists (This group is composed solely of explicit atheists).
Also the two are not two different claims. The latter category falls into a more specific category than the former.
As you can see from doing a few quick searches, there are many conflicting definitions of what atheism is. Some say it's only people who reject a deity. Others say that those people are a specific kind of atheists (explicit atheists), and the general term atheists covers anyone who lacks a belief in a deity. Which definitions is more valid than the other? I'm not sure I can change your mind on that, but at least you recognize that your definition isn't unanimous.
I may not change what you think atheism is, but at least you now know that all people who consider themselves atheists DO NOT believe God doesn't exist. At least now you know that person who says "I'm an atheist" doesn't necessarily believed what you once though s/he believed.