Answer by taking a quote from the following article:

Wales was born in Huntsville, Alabama, shortly before midnight on August 7, 1966; however, his birth certificate lists his date of birth as the 8th. His father, Jimmy, worked as a grocery store manager, while his mother, Doris Ann (nee Dudley), and his grandmother, Erma, ran the House of Learning, a small private school in the tradition of the one-room schoolhouse, where Wales and his three siblings received their early education. As a child, Wales was a keen reader with an acute intellectual curiosity. When he was three, his mother bought a World Book Encyclopedia from a door-to-door salesman.

Though Bomis had struggled to make money, it provided Wales with the funding to pursue his greater passion, an online encyclopedia. While moderating an online discussion group devoted to the philosophy of Objectivism in the early 1990s, Wales had encountered Larry Sanger, a skeptic of the philosophy. The two had engaged in detailed debate on the subject on Wales's list and then on Sanger's, eventually meeting offline to continue the debate and becoming friends. Years later, after deciding to pursue his encyclopedia project and seeking a credentialed academic to lead it, Wales hired Sanger--who at that time was a doctoral student in philosophy at Ohio State University--to be its editor-in-chief, and in March 2000, Nupedia ("the free encyclopedia"), a peer-reviewed, open-content encyclopedia, was launched. The intent behind Nupedia was to have expert-written entries on a variety of topics, and to sell advertising alongside the entries in order to make profit. The project was characterized by an extensive peer-review process designed to make its articles of a quality comparable to that of professional encyclopedias.  The idea was to have thousands of volunteers writing articles for an online encyclopedia in all languages. Initially we found ourselves organizing the work in a very top-down, structured, academic, old-fashioned way. It was no fun for the volunteer writers because we had a lot of academic peer review committees who would criticize articles and give feedback. It was like handing in an essay at grad school, and basically intimidating to participate in.  In an October 2009 speech, Wales recollected attempting to write a Nupedia article on Nobel Prize-winning economist Robert C. Merton, but being too intimidated to submit his first draft to the prestigious finance professors who were to peer review it, even though he had published a paper on Option Pricing Theory and was comfortable with the subject matter. Wales characterized this as the moment he realized that the Nupedia model was not going to work.  In January 2001, Sanger was introduced to the concept of a wiki by extreme programming enthusiast Ben Kovitz after explaining to Kovitz the slow pace of growth Nupedia endured as a result of its onerous submission process. Kovitz suggested that adopting the wiki model would allow editors to contribute simultaneously and incrementally throughout the project, thus breaking Nupedia's bottleneck. Sanger was excited about the idea, and after he proposed it to Wales, they created the first Nupedia wiki on January 10, 2001. The wiki was initially intended as a collaborative project for the public to write articles that would then be reviewed for publication by Nupedia's expert volunteers. The majority of Nupedia's experts, however, wanted nothing to do with this project, fearing that mixing amateur content with professionally researched and edited material would compromise the integrity of Nupedia's information and damage the credibility of the encyclopedia. Thus, the wiki project, dubbed "Wikipedia" by Sanger, went live at a separate domain five days after its creation.

Why did he say this
Nupedia was to have expert-written entries on a variety of topics, and to sell advertising alongside the entries in order to make profit.