What is the point of the short story, "The Old Man with Enormous Wings"? What do you think Garcia Marquez is trying to say about human nature in this story, especially how some people react to certain situations?

Really this is a thematic question. Garcia was into magic realism. Magic realism weaves realism, in representing ordinary events and descriptive details, with fantastic and dreamlike elements. Garcia poses the question of : if we saw the divine, would we even realize it? A broken down old man with wings does not match the interpretation of a fat cherub or beautiful woman with angelic wings. Would we rebuke it as we rebuked say Christ himself? Take a look at the themes below. These will also be helpful,

http://www.gradesaver.com/a-very-old-man-with-enormous-wings/study-guide/major-themes/