As someone who has worked on documentaries, depending on your definition of “garbage,” yes. They are. Because all of them, every single one, is not only edited to show the biased perspective of both the director and the producers, along with the editor themselves, they are also filled with things like added sound-effects, narration that misconstrues what is going on or just adds emotion when emotion is not warranted based on the original footage, taking things out of context to improve the storyline, etc.

For example, the best David Attenborough nature documentary you can think of is full of artifice. Almost none of the animal sounds in nature documentaries were collected at the same time as the video because they’re usually shooting from quite a distance and either the microphone is too directional, in which case you have to add background noise in post or they don’t have enough of a directional microphone, in which case you have to add the noise you want in post. Occasionally, these days, software is used to isolate certain noises. That, again, is artifice.

So no, you cannot trust anything you see in a documentary. Ever. The only truths you should ever trust in a film of any sort is the truths you learn about yourself from watching it. Anything else could be a lie.