These attacks imply that Linux is not a long-term credible solution.``Nobody ever got fired for buying Microsoft'' is the best way to summarize them.
``No long term roadmap ... and no way to get one'' - Microsoft spokesperson (see: http://www.opensource.org/halloween3.html )
``no intellectual property protection means that the deep investments needed by the industry in infrastructure will gravitate to other business models.'' - Microsoft spokesperson
``Unless Linux violates IP rights, it will fail to deliver innovation over the long run.'' - Microsoft spokesperson.
This kind of FUD is the easiest to counter. As was stated in the ``Halloween Memo'': ``The OSS systems are considered [long-term] credible because the source code is available from potentially millions of places and individuals.'' (http://wwwopensource.org/halloween1.html). That is, the chances of Open Source solutions disappearing from the face of the earth are slim. The source code is always there waiting to be modified if your needs change. A Fortune 500 company needing a change in the Linux source code to add a feature for their own use merely needs to hire a consulting firm to add the feature.
Most of these arguments are a combination of FUD#2 (outright fabrication) and FUD#3 (``spinning'' a Linux strength into being a Linux weakness). Unfortunately, there is a bit of truth in the ``violate IP rights'' bit - primarily dealing with encryption. Public key encryption is patented in the United States and is subject to arms export controls. Thus open source solutions that address security concerns, such as encrypted DNS updates and etc., would violate IP laws if released as open source. There is nothing, however, prohibiting them from being released as closed source atop the Linux platform.