The major political factor that may have influenced the creation of Facebook is the general political atmosphere of liberalism (old style liberalism as in the link below) that prevails in the United States.
Liberalism is an ideology that holds that people should be able to have a great deal of freedom. They should have economic freedom as well as political freedom. They should have the right to enjoy the full use of their property. These attitudes help to create an atmosphere in which capitalism and entreprenuerialism can thrive. People have the freedom to pursue whatever sorts of ideas (like Facebook) they have and they have the incentive to do so because they can make a profit if they succeed.
This general atmosphere of freedom is the most important political factor influencing the creation of Facebook.