I find them significantly within the spirit. Private trackers have robust request-filling communities that create tools to automate and upload them. A big part of file sharing is reciprocity. You need to seed torrents for other people to be able to access them, if you use torrents at all. If I'm going to personally spend money on an ebook (or a physical book), rip the DRM/scan the book, and spend my personal time improving the formatting, I expect something in return. Not directly, but in a community sense, where all that time I spent delivering the book to someone who requested it is returned by someone else when I make a request for something I can't access. And I frequently see a return, which motivates me to keep uploading more. Ideally, the file makes its way to public trackers, but I'm not doing all that for random people on Piratebay who don't even seed their torrents. Without people in private tracker communities, public trackers would never get anything but the most popular content. Nobody on public trackers is going to dig out a dusty 1970s tome from their university library and spend 8 hours scanning and fixing it for the masses.