Exactly!
How many government websites use Wordpress? - answer that you Wordpress supporters!
How many governments can actually spell WordPress? But seriously folks, marketing and ignorance is the reason why governments prefer Drupal; sort of like choosing Apple products instead of Android or Linux. From a article in FCW.com:
According to Balter's analysis, WordPress is in a distant second place in the .gov domain. WordPress is used by the Health and Human Services Department, Consumer Protection Agency, Commerce Department, and several others. Both Drupal and WordPress are open source content management systems.
Balter and other experts are questioning the basis of Drupal's skyrocketing popularity for government and wondering why WordPress is falling behind.
"When you stack the two side by side (or against any other CMS for that matter), WordPress is objectively the prudent choice," Balter wrote. "On paper, you'd be hard-pressed to make the case for anything else. But, it's not a technical problem. It's a human one. It seems that WordPress's greatest asset - ease of use that has resulted in widespread adoption by a largely non-technical user base - is threatening to become its greatest liability."
For government purchasers, Balter suggests, WordPress may be suffering from an image problem.
"Among those empowered to make purchasing decisions, there seems to be a sense that WordPress is what you use on the weekends to post pictures of your lunch while Drupal is what you use for 'serious' business," he added.
Balter also said marketing by Drupal to government clients may be a factor. Other experts also have questioned the disparity, suggesting that while WordPress is lower in cost and effective, more organizations want to follow the example of the White House and use Drupal.
Here's the link to the entire article for those interested
and keep in mind you have consultants milking the government teat so to speak:
http://fcw.com/articles/2012/03/07/wordpress-drupal-content-management-.gov.aspx