Its an absolute, absurd misunderstanding of how things get made to single out any particular story and say, Why isnt this, that or the other thing [included]? answered Joel. Its a fundamental misunderstanding of how stories are written. So you have to start there and say, You dont know what youre talking about.
You dont sit down and write a story and say, Im going to write a story that involves four black people, three Jews, and a dog, right? Thats not how stories get written. If you dont understand that, you dont understand anything about how stories get written and you dont realize that the question youre asking is idiotic.