This documentary probably doesn't begin to tell the reality of both sides that came to a tragic head when Marv Heemeyer enacted the ultimate "payback". To truly get a picture of what the dynamics at play were we need to have some more folks who knew Marv and have his backstory meticulously fleshed out. Why not? The whole film rides on Marv's final actions so shouldn't we be more privy to his life up until this point? I'm looking to wholly and not coincidently explain how this all came to be.
Anyway, Hollywood loves revenge movies as we all know. Strange as it seems when it is real it is something to absolutely loathe, especially in the case of a man who unprovoked would have just been a "muffler store" owner.
Perspective-wise: no one was injured and only the protagonist died by his own hand. That is still tragic but we all know if this is wholly despicable or not depends on how band Marv was truly treated. That is the flaw here as I just do not find enough even-handed research to shed light on everything the led up to Marv's final, seemingly quite clear-headed, reality break (he wasn't a Blues Bro., but he felt he was on a mission if you follow).
See this. It is a sociology fiasco of unparalleled proportions. It might have been more deadly and it is quite fortunate it wasn't. As such it is a study in human behavior the viewer may well hunger for a more in-depth explanation.