Its scary because something like this really happened! An unknown US senator and a rich American socialite and a few CIA agents manage to fight a covert war all by themselves! Together, the film shows, they manage to decide the destiny of a nation - Afghanistan. The senator, Charlie Wilson, moved by observing the plight of the Afgan refugees decides to arrange weapons for them so that they can fight their holy war against the evil Russians! He manages to pump in $1 Billion into Afganistan without any one knowing about it! The fact that powerful individuals can decide the fate of nations is scary as hell... the recent Iraq war appears more into perspective. The films is also scary because it shows how easily a rich woman is able to influence the policies of the most powerful nation in the world and manages to give the covert war religious hues (and this was the 80's way before 911).
It is sad because, Charlie Wilson, had a, lets say, questionable character, was known to support dictator Somoza, had arms dealers as friends and had no qualms using Afgan people as cheap troops to fight American war. It is a sad film because an actor like Tom Hanks endorsed it.
But most of all the film is arrogant because it treats us viewers as nincompoops who are supposed to believe that Charlie Wilson's war was a just war, a holy war and a war of a lone warrior who was driven by the zeal to do good to the Afgan people. The film wants us to believe its alright for a few good men to have god like powers in their hands, it wants us to believe arming the mujahideens was a noble thing they just botched up the follow-up efforts after the war. The film wants us to believe all this and much more because its arrogant. Triumph of the Will did a much better job.
By the way, the acting is regular, script is smart quiet entertaining actually but not enough to hide the absurdities. Enjoy. :)