To be fair there'd be no way it could ever be 100% accurate - this is how it goes in real life too. Ask 100 participants in the Facebook history how it all went down you'll get 100 different versions of the story.
That's true, but I think it is a little worse than just accounting for multiple perspectives. The movies is based on "The Accidental Billionaires," whose author didn't interview most (any?) of the main participants other than Eduardo Saverin. When you combine that with Sorkin's loudly proclaimed internet ignorance, I think you can end up with a great movie, but not one that is particularly related to a careful analysis of the 100 different versions of the founding story of Facebook. In The Accidental Billionaires, "Mezrich allows that he invents dialogue, synthesizes details, and puts imagined thoughts into his characters’ heads." If you want a less sensational book, but one where the author interviewed many of the principals I'd suggest Kirkpatrick's The Facebook Effect