Sorry, but every "culture" does NOT have such a sense of failure.Which brings about my point about the brokenness of man that you denied.
Why does every culture have a inbred sense of failure? Some moral standard they fail to meet. Why does moral failure exist?
Every RELIGION has that. Because religions NEED to invent a problem, in order to sell you a solution. If they can't tell you something's wrong with you, then they can't tell you that they alone can fix it.
Nobody's perfect, but everyone can strive to be better. And they DON'T need magic stories in order to do it. We aren't "broken" just because we can always find ways to be kinder. And we CERTAINLY aren't broken just because we picked the wrong world religion, or none at all. What kind of "perfect" god creates broken humans? Moral failings exist because people can choose to harm to one another, as easily as we can choose to do good. The process to correct that is WORK. It isn't solved just by kissing invisible ass.
Here's the thing about your "alien" hypothesis, and your focus on ONE moment in the biblical narrative. In order for your alien story to be TRUE, it needs to explain the WHOLE Bible. Charles Darwin didn't suggest that evolution explains finch beaks BUT NOTHING ELSE. He realized that it explains the ENTIRE range of speciation, not just "one moment". It didn't just explain finches, while failing to explain beetles, dinosaurs, wolves, mushrooms, humans, manatees, Escherichia coli and earthworms. Evolution covered the WHOLE gamut. That's what made it an accepted scientific theory.
But, while your alien idea is fascinating, and MIGHT explain a visitation to ancient humans with the delivery of advanced ideas (though I've yet to see any "advanced ideas" that humans couldn't come up with on their own), the alien hypothesis fails because it doesn't explain ANYTHING ELSE.
It doesn't explain the story of the Garden of Eden. It doesn't explain magic fruit with the knowledge of good and evil locked inside. It doesn't explain talking snakes (or donkeys). It doesn't explain a man arising from mud, and a woman arising from his rib, circumventing the process of evolution. It doesn't explain the formation of language from the Tower of Babel. It doesn't explain Jonah & the whale. It doesn't explain Samson. It doesn't explain Jesus. It doesn't explain the collection of animals from the entire globe, their storage, feeding, watering and waste disposal aboard one boat for an entire year, and then their global re-dispersal. It doesn't explain Joseph's dreams. It doesn't explain Elijah's bears. It doesn't explain why these aliens endorsed slavery, or rampant misogyny. It doesn't explain their aversion to tattooing, or haircutting, or fabric blending. It doesn't explain Jacob's colored goats. It doesn't explain Pharoah's hardened heart. It doesn't explain the parting of the Red Sea. It doesn't explain the walls of Jericho. It doesn't explain dragons, unicorns, satyrs and cockatrixes. It doesn't explain Heaven or Hell.
Sorry to run on, but that's the kind of nonsense that fills the Bible. All these gaping holes undermine these "aliens". A good hypothesis is UNIFIED. It's proven correct when it fills in ALL the holes. You can't just sweep all these dangling threads under the rug. Interstellar aliens, with hyper-advanced morality and technology, would be able to explain EVERYTHING, not just ONE vague possibility.
You can SAY that you don't have "all the answers", but if Darwin had stopped there (or Copernicus, or Newton, or Curie, or Einstein), then HIS theories would've been "brushed aside", too. I'm justified in brushing aside these aliens, if they're nothing but a band-aid on ONE inconvenient story. The Bible is too full of magic and myth for aliens to explain ALL of it.