Have you got a news article to link to, at least to give us an indication of the country (presumably US)?
I don't know what (if any) obligation the ISPs in the US are under. In the UK it's currently a reactive one due to the stalled implementation of the Digital Economy Act; ISPs will block a site if they're given a court order to do so, but aren't obliged to go to any more onerous terms than blocking that site.