Now doesn't this sound familiar, one group finding a native people, wreaking havoc on them with disease, and forcing out the natives who would not work with them. This is pretty close to the story of the Native Americans. The European explorers found the Native Americans, wiped out mass amounts of them with western diseases, and drove out the ones who wouldn't give up their culture and land to the explorers.
My theory is that Bradbury put did this as a warning, to discourage us from overextending in our explanation. To tell us to stay in our domain, lest we cause even more damage to other cultures.
