[evanisthat!]

I am inclined to take the teacher's side on this. I've played in the orchestra at my high school for the last four years, and this seems like an issue we often ran into. Most classes are just groups of individual learning, with the occasional group project, but the vast majority of the work is individual. However, when the teacher creates a group assignment, everyone is forced to participate. This was an issue in the orchestra because if someone did not know their part, the entire group suffered. The original assignment is similar in the sense that it seems to fail to achieve its goal when not everyone participates. As a result, in orchestra, our orchestra teacher often guilt tripped us, punished us with incredibly hard assignments, and has been a general jerk for the last 4 years. For instance, he once walked out of our class yelling "this is why I am an alcoholic!” Alas, the teacher is in the right, and besides the essay he assigned is not that hard, my AP English teacher gave us 11 AP essays (from previous years) due the next day, and it wasn't even to punish us...
Good luck!