It's pretty easy: there's no culpability on either side. It's not either-or. If guns and ammo and knife manufacturers are not responsible for murder than neither are ISPs and software developers responsible for piracy.
If the courts don't like that an IP isn't a person, then they can pressure congress to change the laws. Until then, everyone can go fuck off
I would argue by virtue of their constant bribery.. I mean lobbying.. that each of their votes is more like 2 million votes as far as getting policy changes enacted...
Although, the primary intended use of torrents are p2p filesharing, unlike any kind of weapon whose primary purpose is to cause harm or kill a living thing.