My first Doc Talk column, which honestly feels much longer ago than January of this year, was centered on news that chimpanzees were shooting their own non-fiction films as part of a BBC special. The idea inspired me to complain about the seemingly growing belief that anyone can make a documentary so long as they've got a camera and a subject or cause worth documenting.
To publicly answer a recent, related tweet from Errol Morris (which he appears to have deleted but which is still viewable through others' retweets), yes, yes, yes, it's very possible and very common for there to be bad movies made about good subjects and worthy causes (frankly, I think Morris' Standard Operating Procedure counts). And the reverse is also definitely true (see Triumph of the Will).
This becomes more and more apparent the more docs I see. And since the start of this column I've probably seen more in the span of these last nine months than I had in total beforehand over the course of my 33 years (and I already saw more docs than most people to begin with). But that's the case with anything. The more you get of anything, there's a probable increase of bad along with good.