There is a strain of atheism that rejects belief in God not (only) on empirical grounds, but also because such a God could have no claim to any kind of moral authority. On this view, God is no different in principle than an all-powerful dictator, who issues laws that are not subject to rational scrutiny and cannot be changed by the people who must live under them.
The reply of the religious believer to this is that God is a fundamentally different kind of thing than a human dictator, such that God's actions cannot be morally evaluated in the same way a human being such as Saddam Hussein's actions can be morally evaluated. But this reply lays bare what is at the heart of the matter, which is an ontological disagreement about the possibility--and coherence--of there being fundamentally different kinds of things in the world where different metaphysical rules apply, versus an ontologically flat, materialistic world in which no chunk of matter has any metaphysical privilege over any other chunk of matter.
What I like about this atheist challenge is that it unveils the nub of the difficulty of trying to analytically compare contradicting ontological claims--the one has no truck with the other. For the atheist analytic descriptions of the divine cannot be differentiated from assertions of a profane magic that accompanies certain convenient objects and texts; for the believer, attempts to describe divine being itself run into the same difficulty as describing a sense modality to someone who congenitally lacks that modality--while you can build descriptions in the object layer with someone who shares access to the metalayer/substrate, you cannot build a description of the metalayer/substrate itself that is independent of a reference to a shared human experience. Religious Man and Profane Man find themselves on opposite sides of a communication barrier that cannot be overcome except by a profound change in one or the other's essential way of being.
However, this does not mean that we cannot tease out certain tensions in the religious believer's ontological framework, because certain kinds of assertions imply certain thing about one's ontology. What I am thinking of here is God's penchant for issuing laws that are universally applied--that is, applied to all actors, regardless of the actor's ontological standing. What a universal law ends up doing is ontologically flattening all that it applies to, because suddenly what matters is the action being done, independent of anything about the essential being of the thing doing the action. Murder is wrong; ok, but if it applies universally than it applies equally to a king and to a peasant, thus in this instance placing the two on the same level. In fact, I would go so far as to say that universality is the key driver of any materialistic, flat ontological viewpoint, precisely because of the ontologically equalizing process of factoring a thing's essential being out of the relevant equation.
In any case, the more condensed and monotheistic the God, the more flat will this God's universal proclamations render the ontological landscape. When a universal proclamation is divine in origin, the separation between the divine and the profane is reinforced. However, this separation is doubly reinforced by the fact that these proclamations do not apply to competing entities in the divine space--another, different set of proclamations governs these intramural squabbles within the divine space. So for example, the Hebrew God says "do not kill", which is a diktat to the profane world; however to deal with rival gods, is not a question of binding them to the same rules as the profane mortals must abide by, but rather, attacking them along the appropriate ontological vector: "do not worship those other gods". For an early monotheism that is struggling against a bevy of polytheistic rivals, then, the divine space is a large and bustling one and its protrusions into the profane world many: false idols abound. However, later on a mature monotheism becomes the victim of its own success: with all competing gods eliminated, the divine space contracts to a single point and loses its vibrancy. Without an element of drama to sustain it, it recedes from human awareness except as the 1-dimensional, inscrutable source of universal proclamations that now apply to the whole world--and flatten the whole world--except for that one tiny little dot.
And so the monotheistic religion enables its self-destruction by stultifying the divine and reducing its chaotic protrusions into a profane world increasingly bridled by human will, in the forms of scientific investigation, technological innovation, self-organization, and commodification. The atheist who accuses God of moral bankruptcy is representative of a new kind of humanity that emerges, blinking, in a flat materialistic world whose only essential purpose is to provide something for human wills to work on as they aimlessly proceed through history, eating and procreating and--if they're the lucky ones with material wealth--frittering away afternoons watching Iron Man sequals.
