I think you and I are pretty much on the same page, but I still think it makes sense to define atheism as a lack of belief. I absolutely agree that a lot of atheists are abusing this definition to avoid having an argument. There are also a lot of theists that are under the impression that atheists need to be able to prove that God doesn't exist. There are idiots on both sides. The doesn't mean the definition is bad.

Isn't being unconvinced "lacking a belief"? No, because although there are many ways to be unconvinced, all of them involve a positive belief of some sort. You can, for example, believe that I have not provided enough evidence to overcome your skepticism when it comes to Gostak coloration. You can believe that Gostaks are generally red, and that a blue one would be unusual enough to require further corroboration. You could believe that I have failed to meet the burden of proof when it comes to blue-Gostaks, and that being a generally untrustworthy person, I shouldn't be believed out of hand. You could believe that the color of a Gostak is a matter of such importance that mere verbal reports are insufficient to justify your active belief. Regardless, every way you can phrase your stance regarding the Gostak's color can be interpreted or reformulated as a postive belief.

I agree with all of this. However, the positive belief you make isn't about whether or not God (or a Gostak) exists. It's about why you find arguments for God's existence to be unconvincing.

I think it absolutely does make sense to define atheism as a "lack of belief" in whether or not God exists. I just think that when you say that you "lack a belief" in a debate, you need to explain why you find the arguments in favor of the belief unconvincing.

On a side note, I think the "shoe atheism" term is obnoxious. Atheism is a label regarding a claim you don't accept. Inanimate objects don't/can't make claims, so of course it's going to apply to them.