Neither movie really said that violence was necessary or not. However, both explored the idea that war can't be looked at as a simple us good, enemy bad. First of all, people who may not look or seem like "the enemy" might be. Also, as shown in Good Morning Vietnam, not everybody fighting on the American side was good. There was a character who was "just mean" enough for his boss to transfer him to Guam, and there are definitely some shades of grey involved when Adrian discovers his best friend was involved in a bombing which killed American soldiers.
How critical is the film of US decision-making regarding foreign policy measures?.
They are both a bit critical, definitely The Quiet American more so. T.Q.A. shows the American CIA agent as not being able to really understand the effects of his actions, nor the interplay between rival political groups. As a CIA operative, it is to be assumed that he is one of the best-educated and best-trained people there at the time, so it's disconcerting to think we were sending agents out unprepared for the job (although this movie didn't make them seem as lacking in common sense as The Ugly American).
What shocked or surprised you in the film?.
In The Quiet American, I was surprised that Pyle turned out to be CIA. I was also surprised that Fowler turned him over to the Communists for questioning, no matter how angry or hurt he was when Phuong left him for Pyle. I was also surprised that both films have a scene where people who live in their own little urban world are forced into watching a bombing which their friend was involved in. The "Victor Charlies" and their supporters were infamous for being in unexpected places, geographically as well as socially, as evidenced in Good Morning Vietnam, where Adrian Cronauer (Robin Williams)'s best friend turns out to be living under a false name, part of the VC, and responsible for a major bombing. Adrian learns this after this friend saves his life.