Austin Cline rebuts the argument that people become atheists to escape the authority of God, as presented by Robert Morey, in his book The New Atheism and the Erosion of Freedom. Cline correctly rebuts Morey's fallacious argument, but Morey does wander within spitting distance of an actual point.
Of course the immediate cause of someone becoming an atheist is usually examination of the evidence and arguments for the existence of God, which, while clever, are all transparently fallacious or unsound; not just wrong but obviously wrong. Since millions of people actually do believe that a god exists, there must be some actual cause of that belief, a cause unrelated to logical analysis, a cause that does not apply to atheists.
There are actually a few such causes: atheists typically do not fear death; theists almost universally do fear death, their fantasies of personal immortality can be seen as whistling in the dark and do not assuage that fear (it is typically just moved to fear of hell).
Another important cause is a different attitude towards authority; and I suspect Morey at least has a glimpse of this different attitude. Christians, especially fundamentalist Christians, obey authorities because they're authorities. I see this often in fundamentalist apologetics: "God truly is a sovereign, therefore has the right to govern us entirely as He sees fit, and we have no right to question such governance."
Atheists, on the other hand, typically consider the individual to be sovereign: the individual grants authority to an institution because she chooses to do so, because it is in her interests to grant authority. She grants as an individual the authority to investigate, prosecute and punish unlawful killing to the government because it is in her interest to both refrain from killing others as well as to prevent others — even if they dissent philosophically — from killing her. And, if the body or institution receiving the grant of authority does not act in the individual's interest, she can later revoke the grant of authority.
In the atheist view — or, more precisely, a view that leads to atheism — sovereignty does not entail authority over others. Sovereignty is, rather, an ineluctable and inalienable property of each individual, and entails authority only over herself.
It's easy to see that this view of authority is just fossilized feudalism. The ethical and political structures of feudalism are of course complex, but fundamentally grants authority to the king because he is king. There are notions of "good" and "bad" sovereigns, but the subject fundamentally has an ethical duty to even the worst of sovereigns; indeed the only time one can "judge" the sovereign is when his claim to sovereignty is disputed by another claimant. Lacking a legitimate disputant, the subject simply cannot judge the sovereign; she is ethically bound to grit her teeth, obey the king, and wait for a better successor.
Once one abandons this feudal notion of sovereignty and adopts the idea that the individual is sovereign, the Christian apologetic argument from God's sovereignty collapses: Not only does no god exist, but there is no unfilled position of king of kings in which to place an imaginary god.