The ancient AI didn't just turn evil out of the blue
They were turned evil by a rival civilization or maybe even a rival faction of their own species. What the moon OS said is just war propaganda. Continuing and expanding the previous WMG
- Humanity becomes a space-faring civilization courtesy of the technology of the moon station.
- They will make space-faring arks like in, say, Macross.
- The come across the guys who turned the AI and will find out, that they weren't really evil and the events on Earth were "merely" collateral damage of their war against the megastructure masters
- The civilization of the megastructure masters wasn't really destroyed. Sure, there were massive casualties, but their society, their overall civilization is still (mostly) alive and well; The Moon OS was talking bullshit, again.
- The megastructure masters and their rivals will pay Earth a hefty compensation and the events on Earth will inspire them to make peace and ban the production and deployment of killer AI and nanoweapons, mirroring Real Life treaties restricting and/or banning the production, use, proliferation, and so on of WMDs.
The megastructure-builders didn't actually look like humans at all.
- The odds that a bit of genetic "seed code" deposited on a new-made Earth would eventually produce a sentient species that looked exactly like the one that seeded it, after 4 billion years of evolution's twists, turns, and surprises, are essentially zilch. Rather, the Moon's AI crafted the vision it showed to Brian using imagery from Brian's own mind, designed to elicit maximum empathy for the AI Swarm's victims, outrage at its actions, and cooperation in an endeavor to destroy it from the man it needed to send on a suicide mission. That's why it shows a little human girl screaming for her mother, instead of a Starfish Alien with only the most distant biological relationship to early Earth prokaryotes.
