Absolutely not, not least because a great many documentaries were commissioned in the first place in order to put across a particular viewpoint - usually something that the funding body would endorse.colinr0380 wrote:We also shouldn't forget point of view as well.
And this holds true for a surprising number of incontestably great documentaries - Humphrey Jennings's films were almost exclusively made either for the GPO (a commercial concern) or the Ministry of Information (as government propaganda), and the vast majority of eastern European documentaries from 1945-90 were funded by bodies with strong links to the Communist Party, so explicit criticism of its policies was completely out of the question - although imaginative filmmakers found plenty of ways of getting their message across to what were often extremely receptive and savvy audiences.
In fact, looking over John Krish's career, it's arguable that he found it more creatively stimulating to have a definite message than otherwise, even if the ways of expressing that message were often wildly imaginative (for instance, The Finishing Line with its ultra-gory parody of a school sports day, made to promote rail safety).
There are also documentaries that transcend their original purpose - Geoffrey Jones's films are all notionally "documentaries" (and I'd defend the eligibility of every one of them: they were sponsored by the likes of British Transport Films and Shell to promote their businesses), and yet his work has far more in common with Norman McLaren and Oskar Fischinger than he does with that of his more workaday colleagues. As indeed does Len Lye's - and presumably his GPO work like Trade Tattoo is also eligible? And how about a Quay Brothers film like Anamorphosis? Or even the original version of Švankmajer's The Ossuary (i.e. with the spoken commentary)?
(I suspect I'm going to have the exact opposite problem to Yojimbo - I have no problem citing at least fifty documentaries that more than deserve repeated viewings, and whittling it down is going to be a huge challenge.)