Atheists are emotionally stronger than theists

[RoadRunner79]

But I have often been told here;  that atheism is just a lack of belief, and that they are not making any claims.  In which case either theory is null and void.  Because athiests aren't really saying anything; except about their own mental state.

Well, atheism is a lack of belief, so it is a word describing a mental state. But it's something more than just that. It's also a response to the claims theists make.

If you must derive from a mere mental state a specific claim or set of claims, you could start with, "I do not believe that theists have met what I consider to be the minimal criteria necessary to compel belief in their claims."

On a side note, I disapprove of the use of 'theory' to characterize theist or atheist positions, but it's a niggling concern. I get what you're saying.

Just to clarify, I was using the words "theory" and "hypothesis" in reference to the idea, that the amount of assertiveness on a topic is somehow indicative to the subjects certainty of  that topic or their confidence in it. 

And I think that you understand; but again to clarify,  when atheists are saying that it is "just a lack of belief" they are not saying anything about an objective truth, but only that they are merely not convinced.  They are just providing information about their mental state on the matter and not claiming that anything is false.   Otherwise this would be a claim that would have a share in a burden of proof.