It's not the music and movie industries that control the debate (if there were one). Sure, they try, but it is the various news media programs out there which tell everyone about the "piracy problem". The news programs which only give one side, that copyright is a great thing and that pirates are stealing money out of starving artists hands.
Of course, the news media themselves have a vested interest in stronger copyright, since they directly benefit from that copyright. Whether MSNBC, the New York Times, NPR, or Fox News, all of them make their living peddling copyrighted goods that they created. Why would any of them favor a policy or a candidate that would want to limit their (perceived) ability to make money?
It doesn't help that copyright law makes the average person's eyes glaze over faster than a discussion on tax policy, so they just go with whatever the news person on TV told them. They wouldn't lie to make money, would they?