IIUC, the DMCA says that if there's some technological mechanism X that's used to enforce copyright, and a tool Y that is (or can be) used to circumvent X, then making or distributing Y is itself illegal (as opposed to the act of using Y to circumvent X, which is already illegal even without the DMCA). The DMCA then provides a notice-based method for 'taking down' online copies of Y.
In this case, X is the Admiral technology. Copyright owners use it to control access to content. However, an adblocker with Admiral's domain on its blocklist is a tool Y that circumvents that.
In this case, X is the Admiral technology. Copyright owners use it to control access to content. However, an adblocker with Admiral's domain on its blocklist is a tool Y that circumvents that.