The Sky People

I wasn't quite sure how to take this story. Supposing we used Leopold's definition of "land", the sky people make obvious characters out of the land. I couldn't tell, however, whether their interaction with the earth people was positive or not. Clearly, the sky people were afraid to begin with, but the earth people treated them well, which would bode well for the people's general interactions with the land. However, the speaker makes a point of stating that most people did not act that way, but that this particular couple happened to be polite. If we are to take from this that the earth people were generally not kind to their land, why would the story focus on those who were good? It certainly doesn't make as strong a statement as it might if the sky people were completely rejected or locked up permanently. To cause further confusion, the sky people never return to earth once they've been treated nicely. Are we to assume that the sky people (and, therefore, the land) are by nature sneaky beings who reject kindness? I'm sure this story and its morals were evident to the people among whom it originated, but to someone so far removed, it is practically unable to be interpreted.