There are many ways to look at “Tread,” the Netflix documentary about a June 4, 2004, rampage through the town of Granby by local businessman-turned-killdozer-driver Marvin Heemeyer. It’s a documentary, first, and a highly detailed one at that. It features blow-by-blow re-creations of the events leading up to that widely publicized day in which Heemeyer destroyed half of that tourist-friendly Colorado mountain town with a modified bulldozer (or “killdozer,” as it’s been frequently called) that featured bulletproof plates, video cameras and a .50 caliber rifle. But it’s also a reminder that small-town politics aren’t always a microcosm of the national stage. Through delusional audio recordings he left behind on cassette (and which narrate the film) Heemeyer rants about perceived slights and conspiracies.