They aren't organized by the Sate. They have no official authority. So they aren't really a Militia.
They are a literal gang.
Stop calling them Militia.
It's a term used to describe a military force comprised of civilians. There's even a modern connotation of being against the state.
a military force that engages in rebel or terrorist activities in opposition to a regular army.
Gangs aren't purely for military purposes, so if the purpose of this gang is an armed attack against a govenrment agency, then it's not unreasonable to call them a militia.
Because that's how you get reactionary keyboad warriors going "OMG ACAB WHY ARE THEY ARRESTING THEM THIS IS LITERALLY 1984" on every website and media outlet. Also, probably firefights, officer-involved shootings, and further inflammation of a situation that was fucked from the start.
People don't tend to use their best judgement when blues are involved, especially in America.
Just to clarify, as far as I can tell, the trucks were reported by the National Guard to the US Forest Service who notified FEMA. The other was a call to a sheriff's office about a single individual. It's quite possible these are two actual but different things.