Rob,

If it's so inconsequential to you, why are you here posting?  Clearly you have an agenda you are forwarding, and your proposed definition supports the case you wish to put forward.  You ask, "why do so many Christians feel the need to make not accepting their unprovable views a system of belief?"  Here's my question to you: "why do so many atheists feel the need to deny that their disbelief in God/gods is also predicated on nothing more than belief?"  If it's such a non issue for atheists like you, surely you'd be find with the fact that atheism is a belief system.