Give it a chance you may be surprised. CNN has done some very fine and fair religious (especially Catholic) documentaries.
It seems some just want to hate it because of their political opposition for CNN.
I would be interesting, as an experiment, to find 2 groups of political conservatives who were not aware of the show, and have them view the same film in separate groups, one showing the original, and the second with all CNN headers and mention replaced with FOX News, and see which group thought it was good, and which thought it was bad.