In the documentary space, the biggest and most obvious difference is that in those films you're not in it for a financial gain. It's a piece of collaboration and artistic expression, that pushes change and self expression, in the sense that everyone has a story.
We must learn to love, learn to be kind, and this from the earliest youth; if education or chance give us no opportunity to practice these feelings, our soul becomes dry and unsuited even to understanding the tender inventions of loving people.