Other people advocate a much simpler theory. When an author tells his FTP server to send a document to anyone who asks, he is the one making copies. In legal jargon, the author's command to the computer is the ``proximate cause'' of the copying. The reader is merely requesting a copy, not making it.
I don't know which of these theories will succeed in court. I also don't think you should have to care. So I promise I won't sue you for copyright violation for downloading documents from my server.
Does it bother you that this should even be an issue? Check out Richard Stallman's essay on The Right to Read.