What Kind of Person are the Authors?
Based on facts from my previous posts and from further examples in 'Freakonomcs' I can surmise that both authors are normally good humored men, but are also professional enough to see the issues in society and face them head on.
The entire 'Freakonomics' book itself is a good example. This book brings up many issues ranging from cheating to "proper parenting". The issues they discuss can be very dark; however the authors find a way to use humor to 'lighten up' the darkness.
Let's take the second chapter where he authors compare the KKK to Real-Estate Agents. In this chapter, the authors do explain what the KKK is and what their actions and beliefs were. While explaining their actions, lynching and radio broadcasts were mentioned. Even bluntly obvious conversation codes were mentioned. However to make the situation seem less dark, they also discuss the actions done my President Kennedy to solve this issue.