The people at fault were the ones who edited the clip to make it appear to be something it wasn't and the people who reacted without knowing all the facts.
This type of thing happens in schools all the time. One student will say something about another, parts of which may be based in fact (or not). The other student or his or her friends believe what was said (or not), and the next thing you know you have students in the hallway screaming at each other, threatening each other, and sometimes actually coming to blows.
I don't know how many times a student would tell a friend that so-and-so had said something about them. The friend would confront the person who had supposedly made the statement. Often a fight would start. But when taken to the office, and made to confront each other in a civilized manner, it was usually discovered that the person really hadn't said anything or what they had said hand been distorted or taken out of context.
One of the things teachers, counselors, and administration have to do is get students to learn to question things and get the facts before taking action. It is also their responsibility (and their parents' responsibility) to teach them that fighting is not the appropriate action to take. Most students learn this by the time they leave high school.
Obviously, some adults, as evidenced by the actions taken against Shirley Sherrod, have not learned the lessons that most students learn in school.
The reporter and news channel who put out the edited video are no better than the student who tattles to his or her friend. The people asking Ms. Sherrod to resign are no better than the student who wants to start a fight because of what was said or what they think was said.
Only when the entire story comes out can people judge for themselves. I personally think apologies are due all around. That's what happens to the students. And if the adults are going to act this immature, then they should be treated the same.