Eh, I think there are important distictions to be made about the specific sense in which a given atheist regards a god not to exist, or a given agnostic argues that existence to be unknowable.
For example, I'm an agnostic, an atheist, and a maltheist, roughly in that order. Insofar as someone wants to call whatever is responsible for the observable Universe "God", the point is largely semantic. It is easy to ask what caused the last first cause ad infinitum and thereby create a space big enough to fit whatever deity or lack thereof most appeals to you, but it's also true that the Big Bang wasn't causally linked to anything "before it" as we normally understand time. There was no "before", so whether the current random result is the result of a sapient creator or a nonsapient process is kind of moot from a predictive standpoint. There's no implicit plan either way, so I'm agnostic and apathetic. I can't see what happened and it had no way of knowing I'd try.
On the other hand, there are rules. These rules are well-tested and follow each other in a way that does not account for statistically significant miracles and are mostly true in the sense that they are predictively useful. Yes, we can't really "know" anything in some abstract philosophical sense, but if I want to know how many apples I have in my hands, counting them is a lot more useful than navel-gazing (unless my hands are resting on my abdomen.) In that sense, we know that prayer doesn't do anything better than placebo and we know that bad things happen to good people and bad at about the same rate, all else being equal. We also know that if we stand on a hilltop in a thunderstorm holding a metal rod, our chances of being struck by lighting don't need to take into account whatever blasphemies we may be shrieking. So I'm an atheist with respect to the observable universe: if there is a sapient, conscious God who thinks in ways we can grasp, let alone affect, they must be very content to pretend otherwise.
And, given the above, if there is some asshole deciding what to do with my heretofore undetectable soul on the basis of what I did with the dogma it inserted into the Universe in contravention of all observable laws, I pity Them. They've put a lot of time and energy into tricking people They made incapable of seeing the truth except by blind and otherwise useless faith, much like many insecure children invent playground games with complicated and unfair rules in order to ensure they win. If They can't find a better use for their time than Hell, or a better way to be worshipped than making us fear it, I don't know what else to do but see about getting Them some help.
So there you go: IMO, whether there is a god at all is unknowable, but whether there exists a god whose existence is statistically significant is a pretty firm "no", and if it turns out there is one anyway and their opinions matter in an afterlife, they're pretty messed up. I'm also a Discordian and part of The Satanic Temple, though, so take the above with a grain of salt, ideally on a hot dog.