The creator, Skullfungus, explicitly stated in a 2010 blog post: "Do whatever you want with these files. Run them. Share them. Print them. I only ask you don't sell them."
Therefore, hunting for the is not piracy—it is preservation. However, if you find a version being sold on eBay or DriveThruRPG, report it. The best PDF is always free. gunderholfen pdf best