A fellow robs my house. I catch him and hold him for the police. He complains, "No fair! Most robberies are unsolved because we lack the manpower to chase every lead!!"

Lie is indeed "unfair" to him in some statistical sense, but I am absolutely not being "unfair" to him in a moral sense.

Or to put it another way, the reality of the Internet as you describe it is that a certain %age of copyright violations go unpurusued. It's a statistical model, just as it's a statistical model that a certain number of robberies are unsolved and a certain number of people are killed by lightening.

Is that unfair? It may seem so when you're being struck by lightening, but someone has to be struck by lightening.

Likewise, given enough copyright violations, someone is going to be called out. Today the blow falls on Elise.