> Rather than simply admitting that there is something at least a little immoral about benefiting from someone else's work without paying for that work You've

> Rather than simply admitting that there is something at least a little immoral about benefiting from someone else's work without paying for that work You've got it backwards. The onus is on you to provide a convincing argument that sharing documents without paying directly the authors is immoral. If the document is useful and popular, then I see no immorality in sharing it without paying the author. For paper books, the readers do not pay the authors directly either, they pay the distributor the agreed price. In other cases, this agreed price is the marginal cost of file download.