Untheism, Antitheism and Atheism

I was recently made aware of a post by Eliezer Yudkowsky on two concepts, related to atheism, which he calls untheism and antitheism. This was a response to my comment (taken from a pseudo-scientist's (John Lennox) site) that "I am neither atheist nor theist nor deist". With this I meant that it is my wish that we lived in a society where religious dogmas and all that were as irrelevant as Bertrand Russell's celestial teapot. Yudkowsky argues that an untheist

would be someone who grew up in a society where the concept of God had simply never been invented - where writing was invented before agriculture, say, and the first plants and animals were domesticated by early scientists. In this world, superstition never got past the hunter-gatherer stage - a world seemingly haunted by mostly amoral spirits - before coming into conflict with Science and getting slapped down.

He imagines an untheist society progressing to the point where they develop science, but without passing through the stage where they were slapped by religion. They have had no need for gods in their society. Suppose then that, at some point, they get in touch with a person from our society who tells them

"The universe was created by God -"
"By what?"
"By a, ah, um, God is the Creator - the Mind that chose to make the universe -"
"So the universe was created by an intelligent agent. Well, that's the standard Simulation Hypothesis, but do you have actual evidence confirming this? You sounded very certain -"
"No, not like the Matrix! God isn't in another universe simulating this one, God just... is. He's indescribable. He's the First Cause, the Creator of everything -"
"Okay, that sounds like you just postulated an ontologically basic mental entity. And you offered a mysterious answer to a mysterious question. Besides, where are you getting all this stuff? Could you maybe start by telling us about your evidence - the new observation you're trying to interpret?"
"I don't need any evidence! I have faith!"
"You have what?"

The untheist cannot understand the argument of the theist. It is alien to them, irrelevant. If the encounter persists, the untheist will develop arguments against the irrational beliefs of the guy from our civilization, at which point, says Yudkowsky, the untheist becomes antitheist. And then, he argues, this is atheism. The argument is nice.

And as for the claim that religion is compatible with Reason - well, is there a single religious claim that a well-developed, sophisticated Untheist culture would not reject? When they have no reason to suspend judgment, and no anti-epistemology of separate magisteria, and no established religions in their society to avoid upsetting?

He concludes thus:

Yet in the long run, the goal is an Untheistic society, not an Atheistic one - one in which the question "What's left, when God is gone?" is greeted by a puzzled look and "What exactly is missing?"

And this is my point too.

He also mentions the following very logical concept: that in a pre-agricultural society, one of hunters gatherers, the concept of good god is absent:

Before you have chiefdoms where the priests are a branch of government, the gods aren't good, they don't enforce the chiefdom's rules, and there's no penalty for questioning them.

Again, this is a very precise observation. Religion was invented to keep people subordinate to a chieftain, a lord, a king, an emperor. It's a cheap substitute of opium for the masses, distributed freely by the rulers.