I will concede that many of them didn't react the way they "should" have, but my major point is this: we don't know what's going through each person's mind. We are too quick to judge. This video is a poor representative of an "experiment." We know nothing about what we watched, and I'd imagine that the clips were selected to make us feel a certain way. I'd say it worked in that regard.
It does make me curious what goes through people's mind during these kinds of events, though. Here's the Bystander Effect Wiki article.