I think the agency in question just didn't get the memo.  The U.S. Government, including the Department of Defense, is using open source software in a big way.  See the following links:

 * http://www.gcn.com/blogs/tech/47100.html

-- Quote from the above link:

''It's worth noting, though, that the House Armed Forces Committee addresses the matter.

"The committee acknowledges the availability of proprietary software and encourages its development and acquisition as necessary and appropriate. The committee believes, however, the widespread implementation of an OSS standard will not only lead to more secure software, but will also foster broader competition by minimizing traditional constraints imposed by an overreliance on proprietary software systems," it stated.''

 * http://www.terrybollinger.com/dodfoss/dodfoss_html/index.html

-- A 2003 report by Terry Bollinger of The Mitre Corp. on the use of FOSS in the U.S. Dept. of Defense.


The Dept. of Defense is likely the single largest spender in the Drupal market; it's just behind the scenes.

According to the same database referred to above, Windows had 694 security holes in the last 3 years -- considerably more than Drupal over the same period.