It is true that if an omnipotent god were to exist it could do anything it wanted to. It is precisely this characteristic, though, that makes an omnipotent god an entirely deficient explanation for anything.
If an omnipotent god were to decide that everyone who hops on one leg for 30 minutes every Tuesday at 2:00 PM would go to heaven, and everyone who didn't would go to hell, and furthermore decided not to tell anyone about this stricture, well, that's what it decides. Such a stricture might appear weird and capricious to us, but who are we to judge an omnipotent god?
The argument against this sort of theistic logic (which the authoritarian fucktard Nathan asserts) is not that it's logically impossible for an omnipotent god to do such a thing.
The question for any assertion is not whether it's true; the question is how can we know it's true. The observation that "if X is true, then X is true" is so trivially tautological that it was rejected as a compelling philosophical argument by Thag, a Neanderthal philosopher c. 283,327 BCE. If the above statement is indeed true, most of us are just screwed that we lack an epistemic basis. Oh well.
We intuitively separate truth from knowledge; we believe there are truth-apt propositions we cannot know. If we cannot in practice know some truth, it is not such a big leap to believe there are truths we cannot in principle know; in-principle unknowable truths is at least an interesting philosophical question. But take the question out of philosophy and into ethics, and the unknowability has some bite.
It is logically possible that an omnipotent god exists, he has granted more or less temporal power to some select group of people (i.e. priests) and communicates authoritatively only to that select group.
It is also logically possible that a group of smart people got together and said, "Fucktards like Nathan will swallow anything; if we tell them that God has granted us power and authority over them (and who is he to question God?) they'll give us all their money and let us rape their children."
Authoritarian fucktards like Nathan (probably an authoritarian-submissive; submissives generally feel impelled to persuade others to join their submission, possibly out of a deep-seated shame at their own cowardice) not only fail to give us some basis for distinguishing between the two cases, but actively deny they have any obligation whatsoever to make the distinction.
There is one absolute necessity constraining any so-called ruler with respect to those he would call his subjects: the ruler must convincingly demonstrate his power to coerce his subjects. I certainly accept the United States federal government as my ruler in fact, precisely and only because I am convinced of the existence of police, courts and prisons, i.e. the power of the government to coerce me; indeed it would be patently irrational of me to deny the government has the power to coerce me. (In general, I don't like being threatened, but how I deal with the fact of the governments ability to coerce me is no one's business but my own.)
Unsubstantiated threats of eternal damnation, however vivid and extreme their imagination, do not constitute coercion. (Indeed the more likely explanation of eternal damnation lies in the sadism (or possibly masochism) of their advocates.) No one's fantasy life, however grotesque or sadistic, has any coercive force over a free-thinking human being such as myself.