The fact that "Chapter 11" refers to bankruptcy is the joke in the quoted joke. Calling this joke a "poorly-understood incident from that period", referring to

The fact that "Chapter 11" refers to bankruptcy is the joke in the quoted joke. Calling this joke a "poorly-understood incident from that period", referring to Warren Buffett's books as books of the Bible, and saying that "the meaning of the story remains unclear" is the joke on this satirical page, in keeping with the premise of being written in 20002 when details of the first few millennia are ancient history and neither "dollars" nor 20th/21st-century US laws are remembered.