Interesting point. You could argue that a (good) counterfeit Louis Vuitton bag or Rolex provides the same functionality as the original, without the 90% tax to the rights holder.
So, maybe the situation is quite analog: The paper you download is actually more or less the same as the original, but you haven't paid the rights holder, so it's counterfeit.
It isn't. You're getting literally the same paper.
It's like I bought a bunch of Louis Vuitton bags and, for some reason, decided to sell them off for a fraction of a price. If you bought one from me, you'd buy an original bag, not a counterfeit one.
So, maybe the situation is quite analog: The paper you download is actually more or less the same as the original, but you haven't paid the rights holder, so it's counterfeit.