Follow-up question: how come the Usenet providers are not caught in this dragnet?
Usenet is not immune: http://torrentfreak.com/newzbin2-the-mpaas-usenet-enemy-1-ca...
For all practical purposes, they have become the same thing. Courts are not obliged to accept carefully worded definitions when the technology involved is a mere instrumentality.
Also, even if we do accept the description argument, you still have to consider that it's a description of how to obtain someone else's property. The first amendment doesn't give you the right to market detailed instructions on how to rob individual branches of a bank, for example, which is loosely analogous to IP infringement (insofar as physical currency is only a representation of a currency abstraction, this is actually a good parallel).
Citation needed.
Relevantly, the section reading:
The Supreme Court held that "advocacy of the use of force or of law violation" is protected unless "such advocacy is directed to inciting or producing imminent lawless action and is likely to incite or produce such action."
This was specifically referring to the case the famous line about "shouting fire in a theater and causing a panic" not being protected speech; it would certainly seem to me that attempting to "market detailed instructions on how to rob individual branches of a bank" would match the exception above. You can publish material telling someone how to make an explosive device, but material telling readers precisely where best to put that explosive device to crack open the safe at the Bank of America office on Fifth Street? Probably not going to survive a legal challenge.
One of the earliest DMCA cases, ALS v. Remarq, involved Usenet. Usenet has the same "whack-a-mole" problem as P2P and cyberlockers where deleting infringing content often results in a different user re-uploading the same content (perhaps with a minimally different file name) within hours. IMO this kind of situation is handled very poorly by the DMCA, but I don't have any specific suggestion about how to fix it.
Make it easy to obtain the content legally?
As a result, binary usenet is more or less devoid of easily searchable content nowadays. It was only a matter of time.
Another way to think about it this: you have some property that has now become a haven of illegal activity (through no participation of your own) that is disrupting the local community. IANAL, but in such a case I'm guessing you could be compelled by the law to clean your property up. Even if the law has no way to compel, shouldn't there be?