Red denotes Islamicist states, or those that openly funded Wahhabi or Islamicist schools and causes.

Blue denotes US allies, or states that tilted toward the West.

Pakistan is considered an Islamicist state at this point primarily because it supported and was aligned with the Taliban, which ruled Afghanistan and harbored al Qaeda.

Saudi Arabia could be considered either Red or Blue, since its government has long been ideologically divided over its close relationship to the US.  But prior to 9-11, its massive funding for the madrassas which instruct would-be terrorists around the world put it in the red camp.