ah, I see a lot of conspiracy crazies on craigslist, and I'm really tired of it.
However, somehow, it looks like there are people putting special effort to propagate the "Dean is an angry guy" myth.
People have taken a hard look at the "Dean scream" speech, and have found that broadcasts of the speech were processed specifically to amplify his speech. Apparently he had to yell to be heard over his crowd. When you hear it in context, it sounds like was just doing what he had to do.
I do want to be fair to the guy
For more, metafilter is always good.