I think the thing to remember when reading the article by Matuszewski, is that it was written when film was fairly new. He was only focusing on showing unfiltered reality like the trains and workers movies. He had no idea that eventually people would edit and manipulate video to show a point of view or debunk another. I do believe that video and film can show the truth. We see it all the time when someone with a camera phone records rally, or an incident of police brutality. However, we see different news stations with different takes on each incident. For one person, truth can be different from another person.
Take for example the Occupy Wall Street movement. When it was going on you had two takes on it. For one side they were revolutionary. They were seen as fighting for their freedom. The other side saw them as misinformed and misguided. So when there was video of a cop spraying mace in their face it went one of two ways. The protesters were being uncooperative and had to be maced for the sake of peace. Others had a different take. Students exercising their right to protest were wrongfully maced by the police in an act of police brutality. Both are based on the same video which shows the same thing. Therefore the “truth” is not determined by the video, it is determined by the viewer.