Why is the US Army internet-blocking Time Warner?

Noah Shachtman of Wired "Danger Room" blog says,

The military often blocks websites for the oddest and most obscure of
reasons. But this has to be one of the strangest digital blockades to
date. The Army is choking off web and e-mail traffic with all
companies who rely on Time Warner's servers for their online presence.

Link. One Army spokesperson later explained that the block of Time Warner internet services, including Road Runner (above), was in response to a security breach — but the details still sound weird.