Now, some people go through a phase of thinking there’s an omnipotent god, perfect in every way, but then they decide that if that was how things were, then the world around us would be different. There’d be less suffering, or no suffering, or organisms would seem better designed, or people would experience an amount of suffering proportional to the amount they caused, or something like that. This is understandable: the original opinion is a common one to which many people are brought up, and the so-called Problem of Evil is a tough problem for it. What I find hard to fathom is the reasoning behind a common response to the problem. Rather than decide that the god they’d thought was perfect isn’t perfect after all, they decide it doesn’t exist. But isn’t that crazy? If there’s evidence for divine agency, then there’s evidence for a divine agent as good as the actions and omissions attributable to it. If I’m right, then the proper response to the Problem of Evil is not atheism, or at least not the kind of atheism which says there are no gods.
One reason people might respond this way is because they held the former opinion on the basis of authority, rather than more direct evidence for divine agency. The former believer becomes convinced that the authority had something wrong, and this casts doubt on the rest. The beliefs in the god’s existence and its perfection aren’t independent because they have the same source. It'd be like the kid realising reindeer can't fly and inferring that the whole Santa story is probably nonsense. This makes some sense, but not much. The more the authority was trusted in the first place, the stranger it is to throw out the whole story on the basis of one incorrect detail, and the less the authority was trusted, the less likely it is that they were the sole or even primary basis of the person's belief. (Unless they're a four year-old.)
Another reason the perfection-belief and existence-belief might be dependent on one another is that someone might think an omnipotent, omniscient god would have to be perfect. There have been people who thought that all cases of wrongdoing resulted from either our ignorance or embodiment, but I don’t think it’s very usual to think this now, except insofar as all agency requires embodiment, and the believer in divine agency wouldn’t have thought it did. So responding to the problem with atheism would suggest some rather old-fashioned views about the sources of wrongdoing.
The third explanation I can think of is that people decide that they have no interest in what gods there may be unless they’re perfect, or at least very good indeed. So they don’t stop believing as such; they just ignore the issue. I expect this sometimes happens, but it seems reckless, especially if the imperfect god still goes in for divine retribution. Indeed, it’d be understandable if a raised credence in an imperfect god went with a raised credence in Hell. It’s also worth pointing out that this attitude has no place in serious rational inquiry into how things are.
I’m an atheist. It’s not because of the Problem of Evil; it’s because I don’t see any evidence for divine agency, whether of the sort I’d like to happen or the sort I wouldn’t. And I think the Problem of Evil does pose a serious problem to the widely held belief that there’s a perfect god. I don’t, however, think the problem by itself offers much support to the view, also widely held, that there aren’t any gods at all. Perhaps I’ve got the wrong end of the stick and nobody thinks it does. If I have, you can get back to what you were doing. But if you’re an atheist because there’s so much suffering in the world, then I’d be interested to know exactly how that works.