Clearly some people who imagine their networks very strongly appear in the articles (jihadists, for instance), but the theme they all share seems to be that tools once thought of as liberalizing and uncomfortably revelatory (the internet, war journalism, and human rights rhetoric) are increasingly being co-opted by the very people and organizations with which they were previously understood to be fundamentally at odds.
Having thusly written it out, the connection back to imagined networks has become a little clearer to me. This 'surprising' co-optation is characteristic of the very reason we call them 'imagined' networks: no tool is in and of itself liberalizing and revelatory. Only in the context of a large group of people with certain ideas about how they use the tool as well as ideas about the relation in which those ideas stand to those of other people who use the tool can such suppositions about the nature of the tool arise.
Given that these suppositions are wholly a product of the collective imagination of some group of users/witnesses to use, it should be no surprise that not only are other uses possible, but that there can be other, essentially disjoint groups with completely different ideas about what the tool is and how it can or should be used. In the cases pointed to by these articles though, the communities in question are so close in extent to 'the entire Western world'* that they have become transparent. These articles are a valuable wake-up call not just about the tools they discuss explicitly, but about the dangers of imagination in general.
* There are more Western naysayers about the internet than the other two, but belief in its fundamental freedom-causing-ness is still pretty widespread.