Just that really.
That part of the world is incrediably volatile at the moment, even more so since the terrorist attack in Tunisia. The foreign office advised against travelling there after that. I've always wanted to go to and see the pyramids but accept its not going to happen for the foreseeable future, it's not worth the risk . Now this terrible incident with the plane, clearly there is intelligence telling the government that it's just not safe to fly to or from there at the moment.
Aside from that, I've known loads of people who've been there and none have liked it. Huge purpose built resorts with gates and armed guards on them?! No thanks! I'd never be able to relax.
If you want some winter sun what's wrong with the good old Canaries?