Too Much Voyeurism
I walked out of the theater loving this movie. Then the feeling crept in, and eventually crowded out all of my enjoyment of it. From beginning to end, the movie is a blatant invasion of privacy. About as obviously as any person who ever existed, Vivian Maier would not have wanted any part of her life to be made public. They sheepishly address this without really dealing with it. And they cling tightly to the one piece of evidence that supports them, while dismissing the mountain of evidence that contradicts them.
* NOTE: If there was anything to refute what I'm saying, then maybe they should have put it in the movie. And if other information turns up after the fact that confirms the producers' hopes, it wouldn't excuse what they did in making this movie.