[mikeash]

Let's say I stand in front of your doodad store (imagining you only sell it in a store, for whatever reason) with a megaphone, repeatedly giving an extremely convincing speech about why people shouldn't buy your doodads. Can you claim that I've hurt you then?

Many of the people I talk to would never buy a doodad anyway. Those result in zero harm. Some of them were going to buy a doodad, were non convinced, and bought anyway. Those also result in zero harm. But some were going to buy a doodad and then decided not to. That's harm.

Piracy is the same. Many pirates were never going to buy the thing anyway. Many people purchase anyway. But some non-zero number of people would have purchased but now don't.