It's of course tempting for storytellers to make their characters one-dimensional. In this case the makers of the movie decided to portray a singularly good and humanitarian Gandhi. Usually we see purely good or purely bad characters and know they are good or bad because the movie tells us. We usually don't know why characters are bad, other than the fact that they're fighting against the main character, so they must be.

The problem is this makes for boring characters. I love it when I see more complex characters and their motivations. I know that's not exactly the Gandhi the movie makers wanted to portray, but maybe it would have made for a better story.