Why not be an agnostic Catholic? People are not simply agnostic, they are agnostic somethings, either atheists or theists. Agnosticism isn't a middle ground, a fence sitting position. It is a positive assertion about the nature of knowledge, of what can be asserted as factual (or virtually so) and what must remain forever within the realm of belief. You can be agnostic in that you will not assert beliefs about God(s) or lack thereof as factual, but you will still have those beliefs. If you belief that because of the agnostic assertion regarding the nature of knowledge about divinity, that it is an area of fruitless speculation and you don't want to bother with it, I think that still puts you in the ranks of agnostic atheism.