I am sorry but that is pure BS. You are reaching to cover yourself. Documentary is a spin off of journalism ... and journalistic imagery started with stills. The same methodology you stated which distorts still photography into a non-documentary form also applies to movie and video ... the movie/video camera can record wide or tight ... from low to high angle ... et cetera.
All forms of human communications reflect the source from which they are generated. This does not make them false or not valid. Documentary image recording people, (whether they be movie/video/still/written word), generally, are trained to tell the story objectively ... or as objectively as the circumstances permit.
Albeit, a wide angle image may reflect a different viewpoint than a telephoto image, but both document a scene truthfully. This is why major market news organizations won't hire a photographer that doesn't have a degree in communications/journalism ... because documentary photography isn't about good photography ... it's about telling the story through imagery. And telling the story is all about accuracy.
Additionally, because all documentaries reflect, to some degree, the person who is generating the report ... it is always prudent to gather information from a number of sources when formulating an opinion on an important matter/subject.
Gary