From what I understand, Mr. Bethel didn't write his account for a commercial venture, he told it online for free. His being a journalist was peripheral to the story itself. Of course, it meant that it was far better written than most peoples' personal encounters, and I'm sure that contributed to its popularity. He also had little to do with how the story took off afterward and became an urban legend.
Believing he's sincerely relating something that happened to him is not the same thing as believing his impressions or conclusions about it are objectively true.