Well first of all it seems like (a) the author of the poem didn't explicitly agree to sell it at the price and (b) people are often willing to pay unfair prices for things in times of duress (IE... how much would you pay for a bottle of water if you were dying of thirst?).
And either way, the author isn't making a legal or moral argument one way or the other. He's just telling a story about his emotional response to this complicated and unique situation. The fact that the people on the other side of the story effectively have infinite wealth and still made the decisions they did is important to the story! It makes it easier for us to understand their motivations. He's a writer who wrote a story, it's not a wikipedia entry.
And either way, the author isn't making a legal or moral argument one way or the other. He's just telling a story about his emotional response to this complicated and unique situation. The fact that the people on the other side of the story effectively have infinite wealth and still made the decisions they did is important to the story! It makes it easier for us to understand their motivations. He's a writer who wrote a story, it's not a wikipedia entry.