Fun fact; Matt Damon was portrayed as a derpy character in Team America because the doll used in the movie just came out that way by accident. By the time the crew realized it, it was already too late to change the puppet so they just decided to build the character around the doll.

Source: http://www.reddit.com/r/IAmA/comments/1x6q4r/matt_damon_ama/cf8kjno

Here's what Matt wrote in his Reddit AMA:

What did you think of Matt Stone and Trey Parker's portrayal of you in Team America World Police?

I thought it was brilliant! I mean, I never understood it, and then I heard an interview with them and they said the puppet came in looking kind of mentally deficient and they didn’t have time to change it, so they just made me someone who could really only say his own name. All the comedy they’re doing is really next-level stuff. Also, I liked being included as a person who was against the Iraq war.