Well, I don't buy this view, but Wutteat would simply be a tekne concoction and the memory of other worlds would be false.
This is how it would work: ages and ages ago a nonman sect went into what would later become agongorea. They did all kinds of crazy things to change themselves to avoid damnation. A key part of their plan was to convince themselves completely of some kind of past myth--the way the republic needs a back story that the people just popped into existence with false memories. With the Ark built and the delusion machine working, they blow up the surrounding lands and submit every last one to memory altering device.
Why? I have no idea. I can't remember who, but someone said Kellhus was the "the breath that is ground" playing the prophet until he became it. Maybe their plan is similar, play the space alien until something. Crazy! I'm just trying to think of all the ways the main groups could be massively deceived, cause I think Bakker would do some of that.