The front page of Drupal.org provides a statistic with the number of "countries" where the Drupal community is from. This number is higher than various official lists of countries, such as the list of sovereign states on Wikipedia. The Drupal community is made up of people from all over the world, including some places that are not officially recognized as countries. However, we support everyone's right to identify themselves in their own way, and provide some additional choices in our "country" selector to accommodate members of our community that live in disputed territories.
To request adding another country to the list, search for an existing issue in the Drupal.org webmasters issue queue, and if none exists, create a new issue about it.