I meant more in the way: if the user downloads a book whose source is not known to be legal or illegal, and he or she gets sued for downloading it, it's up to the prosecutor to prove that the user has downloaded from an illegal site. Here it's being stated that, in case of doubt, you're guilty, without needing to prove that you're effectively downloading from an illegal source.
Spoiler:
As for the copyright thing, I know something of it as a
C4SS contributor, though of course those are my personal views and they don't belong in this topic.