I usually use the download button on AO3, but I also leave kudos and sometimes a comment. I just don't have enough time to read something right that minute, but I want to read it later. It also links back within the pdf file so that you can go back and leave a comment. So, I get that, but the whole distributing it without the author's permission, without the author knowing, and for a profit, just pisses me off. It's not cool at all.