I don't understand the atheistic push that "we don't believe, we lack belief". I really don't get it, it seems rather pretensious almost
I don't think that's pretentious as it perfectly describes a certain position. Which is not knowing, and thus choosing not to believe.
For example, personally, i don't know whether or not there is a god(s). No idea whatsoever. There might be and there might be not. So, while i was once a believer in a god, i decided to step back and stop embracing this idea and stop acting based upon it.
That is
not the same as acting as if there is no god. It is exactly just this: acting as if you don't know whether or not there is one, and as such, you neither base your foundation upon the idea that there is a god, or the idea that there isn't one.
This might be in essence the same as agnosticism, or at least one definition of it, but it also fits the "lack of belief" definition of atheism. And, most importantly, this is a real distinction and a different mindset to that of there not being a god. It's not mere word play.