Imagine getting a message like this out of the blue, not even knowing who's after you. What are you going to do?
It's hard to fight a faceless enemy, especially when you can't even be sure if they really exist.
Protestors in Syria or China could probably already guess what such a message means, so I'm curious as to the amount of information needed for a person to be able to act on it?
As Snowden demonstrated there's no lack of westerners being spied on just because they happen to work at a telecom company.
The fact that there's no more information provided makes it far too easy for those people to just ignore these warnings as mistakes and go on with their lives.
I don't know if Facebook is going to be showing this to any western people, but when google showed me their version of the warning there was very little I could do with it since looking through my logs and emails showed no signs of any attempted attacks.