Look at Super Size Me . The trailers, news media, promotions, critics, broader news media presented it as an objective case study. And McDonalds canceled a popular sales promotion over it. *and it had an enormous negative influence on McDonald's reputation, that it still hasn't yet recovered from.
90+% of people watch and share documentaries with the perspective that they are objective, truth seeking works.
https://en.wikipedia.org/wiki/Super_Size_Me#Counter-claims
But I was unsurprised, years and years later, to discover that Spurlock's extensive and growing liver damage, and other adverse symptoms, were being helped along quite a bit by his severe alcohol abuse throughout principal photography. It really sort of drove home that there is more than one side to this story they put up on screen, no matter how much they appear to seek and depict the truth.
Thousands of through-hikers live on McDonalds and Ramen for months and are some of the fittest people. Dozens of other activities like this too.
Kohen lampoons subjects in candid videos but at least presents his works as a joke, and we're all in on it.
This movie is the exact same thing, but it's promoted as an inside & sincere look at Holmes, when it's really just the Ali G schtick.