Thanks for the pings and support, both of you.
I wrote the thread in a mature post that was already several days old, primarily as an exercise in organizing my thoughts. I didn't think anyone besides @gabe would see it, so I'm really pleased it has reached a larger audience and brought more attention to the instance.
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.