It's in a different jurisdiction than Gutenberg (Australia). You can't find any George Orwell books in Gutenberg, because his books are not in the public domain in the United States just yet.

Australian law says life + 50 years for authors that died before 1955. That'd make Orwell's work in the public domain since 2001 in Australia, and in the US starting from next year (died in 1950 + 70 years). For convenience copyright for those that died 70 years ago expires on January 1st next year, not exactly 70 years ago, so the author that died on January 2nd 1950 an author that died on December 31st 1950 enter the public domain at the same time: January 1st, 2021.

Project Gutenberg has a standard footer for their books that includes "Project Gutenberg is a registered trademark, and may not be used if you charge for the eBooks, unless you receive specific permission."

So commercial use actually requires that you strip Project Gutenberg's trademarks and redistribute only the public domain text.