Possible that because of the instability recently Eqyptian 
  authorities think Facebook is more capable of serving web 
  pages than their own sites?

Nike, McDonalds and Coca-Cola have Facebook pages they often update. Hamas and the IDF even have twitter accounts.

Perhaps it's not that they think their website is unstable - but that they think communicating with the public through Facebook and Twitter is part of the future of public relations.