Much of this story's brilliance lies in just the last sentence. With just one subtle brushstroke Clarke manages a delicious pay-off hinting at a very dark, but expectable¹, outcome.

1: The whole 'humans are assholes'² trope has been explored much more since the 1940s, so I expect the ending might have had even more of an impact back then.

2: Literally, in Spaceballs, of course.