Because you are still contributing. The DMCA is the only thing that provides the safe harbor to prevent this claim. It's the only good part of the law.
The DMCA is the only thing that provides the safe harbor to prevent this claim.
Is this really true? Is there case law pre-DMCA that showed that website owners or ISPs were being forced to pay large judgments for copyright infringement even when they showed that the infringer had violated their terms of use?
I understand that without the DMCA, the claim could still be made, and that it might cost a website owner or ISP quite a bit of money to defend it in court. But that's more a sign of how broken our court system is than anything else; the way to fix that is to raise the penalty for frivolous lawsuits. "Loser pays" would be one way to do that.