[thinkmassive]

Most code written for government use is not written by government employees, but by contractors. Here's the second paragraph from the section you linked:

"However, when a US federal government agency uses contractors to develop software, that is a different situation. The contract can require the contractor to release it under the GNU GPL. (GNU Ada was developed in this way.) Or the contract can assign the copyright to the government agency, which can then release the software under the GNU GPL."