Quoting Wikipedia quoting Wiseman:

Wiseman’s films are, in his view, an elaboration of a personal experience and not an ideologically objective portrait of his subjects.
In many interviews, Wiseman has emphasized that his films are not and cannot be unbiased. In spite of the inescapable bias that is introduced in the process of “making a movie”, he still feels he has certain ethical obligations regarding how he portrays the events in his films:
[My films are] based on un-staged, un-manipulated actions… The editing is highly manipulative and the shooting is highly manipulative… What you choose to shoot, the way you shoot it, the way you edit it and the way you structure it… all of those things… represent subjective choices that you have to make… In [Belfast, Maine] I had 110 hours of material … I only used 4 hours – near nothing. The compression within a sequence represents choice and then the way the sequences are arranged in relationship to the other represents choice. Aftab, Weltz[1]
All aspects of documentary filmmaking involve choice and are therefore manipulative. But the ethical … aspect of it is that you have to … try to make [a film that] is true to the spirit of your sense of what was going on. … My view is that these films are biased, prejudiced, condensed, compressed but fair. I think what I do is make movies that are not accurate in any objective sense, but accurate in the sense that I think they’re a fair account of the experience I’ve had in making the movie. Spotnitz
I think I have an obligation, to the people who have consented to be in the film, … to cut it so that it fairly represents what I felt was going on at the time in the original event. Poppy