If the film does capture something accurately, it's the immaturity and misery of a band that, in spite of those self-insufficiencies, managed to turn out some of the most important music of their generation; happily, whatever the band members' current emotional states may be, Radiohead is still doing the same. In spite of the documentary's shortcomings, one can't help but be amazed that such seemingly morose, disconnected young men were able to put together such persuasively moving music.
Now that I think about, away from the TV and writing, maybe the intentional disconnectedness of the film was appropriate. Here's a clip. Judge for yourself....