For me, it's more philosophical. Consumers need to some self control. We are consuming everything without conscience -- because that's the easiest way. It's easy to eat fish, so the oceans are going to run out. It's easy to consume oil, so the gulf is polluted. It's easy to bit torrent content so people do. But it does cause problems. Some people don't want their content consumed in that way.
To respond to some other commenters below, it doesn't matter if studies show only the middle men are hurt, middlemen are important for the distribution of content and much content wouldn't be known if it wasn't for the middlemen -- they need jobs too.
As for the argument that "people pay after they download it" -- that's simply not true. I know tons of people who download thousands of movies and redistribute them on limewire and never pay for a single one.
If you want to watch a movie and the only way to get it is to use netflix or blockbuster (both middle men) then go there and get it. If you can't get it there or you're too lazy to drive there or you don't subscribe to netflix, then don't watch the movie! Do something productive with your time. Control your desires to consume stuff you haven't supported.