That's not fair. He makes it quite clear at the beginning that the whole story is free but that you will see requests for tips or to buy the DVD.
Remember that this story was written in 1995. Internet advertising was generally not available then, and neither was proper etiquette for advertising. I do not blame him for trying to partially monetize his thousands of hours of effort. After all, it's not like he kept the money.
You're talking about on his website, from 1995, in which yes he made it clear from the beginning, and he also offered the entire story through to the end for free.
We're talking about the article on FT.com (this actual submission) where there is nothing up front about it, and where, without finishing his story, he ends with the fact that he's telling the story live and how if you pay to see him you can find out the end of the story.
Remember that this story was written in 1995. Internet advertising was generally not available then, and neither was proper etiquette for advertising. I do not blame him for trying to partially monetize his thousands of hours of effort. After all, it's not like he kept the money.