Good genre movies are a little bit like trying to write a haiku. There are certain things that you have to do to fulfill the audience's expectations, but inside that, you have complete freedom to talk about whatever you want. Who wants to see a movie about gun violence in America and class? But, if you set it in this terrifying, fun, roller coaster ride of a movie, you can talk about whatever you want. That's been the game that genre movies play, when they do it well.