There are different modes to document events with photographs (or video, or words). You can be, for example, an advocate, a documentarian, or a journalist. These roles overlap and there are not clear distinctions, but they are not all the same thing. (To give an example, I think a lot of Gordon Parks's well known work is documentary, but not newspaper-journalist dispassionate.) Documentarians ("documentary makers" who might work in stills or words, as well as movies) and newspaper reporters have generally different standards for objectivity and independence from the source, but they are both engaged in kinds of reportage. Saying that everything that doesn't meet a particular standard of reporting is propaganda, is often used to discount things that make us uncomfortable.