They obviously never seriously intended to go to print with their book again if such a little torrent discourages instead of incourages them.
Although I'm not in the "printed is always better" camp a reference book like this is much better than a PDF copy when it comes to inserting multiple bookmarks or just leaving it open during coding. On the other hand I'd probably download a PDF in addition to the printed copy no matter if the PDF is legal or not because full text searches in a printed book kinda suck - see www.pragprog.com
for someone who made that into a business model.
But in this case I downloaded the PDF out of curiosity and I never intented to buy the book - I'm not into Amiga programming and I don't think that'll change anytime soon.