The DMCA safe harbors have a requirement that in order for an online service provider (eg the ISP) to be protected from liability for copyright infringement that the ISPs have a repeat infringer policy to (eventually) stop the copyright infringement of their users by discontinuing service to them. Without the DMCA safe harbors the ISP would potentially be on the hook for copyright infringement. With high statutory damages for infringement, that’s a lot of potential money for the group suing the ISP, hence why they would want evidence showing the ISP didn’t have a repeat infringer policy or did have one but failed to enforce it. Testimony from a pirate saying how great the ISP was because they didn’t ban them even after multiple notices would help establish that.

It’s actually more like walking into a gun shop, telling the owner you plan on committing murder with the gun they sell you, and he continues to sell it to you.

The key difference being that the provider knew that your intention was illegal, and they continued to allow it to happen.

The ethics of this are debatable of course, but in general, it seems that facilitating a crime is generally seen by most governments as ‘aiding and abbetting’ and is considered a crime itself.