I think this song is about society's rather unhealthy addiction to drama. It's entertainment. The sideshow is a metaphor for the drama portrayed in media. People are captivated by tear-jerking stories and awful tragedies they hear on the news. And they feed off the sad stuff. They "can't afford to pass it by" because it's "guaranteed" to bring about emotion. They view the people in the sideshow attraction and use them as an outlet. But really, anyone can end up in that attraction.
I think this song is about society's rather unhealthy addiction to drama. It's entertainment. The sideshow is a metaphor for the drama portrayed in media. People are captivated by tear-jerking stories and awful tragedies they hear on the news. And they feed off the sad stuff. They "can't afford to pass it by" because it's "guaranteed" to bring about emotion. They view the people in the sideshow attraction and use them as an outlet. But really, anyone can end up in that attraction.