Okay, given the deficit of imagination here, let me spell it out. My client tells me he will purchase program X for $Y.
Except my client takes the program and doesn't pay because he doesn't believe in copyright, and I've still got the original program, so he hasn't stolen anything (according to many pirates). I haven't lost the program - all I've lost is the ability to economically exploit it. And yet almost all of us will acknowledge I've had my work stolen.
Look, a 6-year old knows that someone who copies your work without your permission is stealing. It's only adults who try and dress it up so they don't have to feel bad about ripping people off so they can get free stuff. I don't care if people pirate, but if they are going to, at least they can be honest that they're stealing because they can get away with it, rather than dress it up in some self-righteous garbage.
Another irregular verb: I pirate his work, he steals my work.