[danarmak]

Admiral's domain serves software that enforces access restrictions to copyrighted content. Including their domain in an ad-blocking list is a way to circumvent the restrictions.

Whether distributing a list of domain names counts as distributing "tools" or whatever the exact language of the act is, I don't know. This other subthread contains a better discussion: https://news.ycombinator.com/item?id=14991624

[goodplay]

I doubt failing to contact a server would circumvent DRM. Blocking their servers would only make their DRM scheme fail and prevent access to said copyright material.

Using the DMCA to protect company's defective and flawed DRM scheme does not constitute circumvention. As such, I do not believe that DMCA's anti-circumvention laws are relevant.

[codedokode]

They might use a scheme that would allow access by default and block it with a script from that domain. So blocking the domain becomes a circumvention (today I finally learned how to write this word).

Or that domain could be used to collect views stats for copyrighted content and make decisions based on that stats. Blocking this domain is obviously messing with copyright protection scheme which is illegal inder DMCA.