If you don’t want your content linked to, don’t post it on the web! Duh!
In this particular case, the problem is that 'they' didn't post it on the web, someone else did.
Of course, they should be going after that person, and not the website that provided a link to it.
Finding who uploaded the file is very, very difficult. Which is why we haven't seen any reports of DHS (or anyone else) going after the original uploader.