I love the short story The Road Not Taken by Harry Turtledove. There's of course the alien invasion trope, where aliens are space conquistadors pillaging the earth with their extra-terrestrial powers, and its complement, the Star Trek trope, where humans are culturally and technologically superior secular humanists descended to a backwards planet. And then there's this story.
I just finished writing a small book in a thread about federation on literature.cafe yesterday, the thrust of which is that moderation, not federation is the threadiverse's killer feature, and when in doubt smaller instances shouldn't federate with larger ones. This list makes a perfect post-script to my point. Do you mind if I crib it? I'm a big fan of what you're doing here. I'd also love your feedback on my observations if you have time.