The federal government was interfering with their business. They did not burn federal property as an act of protest or arson, they burned it to fulfill their obligation as good husbandmen of land entrusted to their care.
The feds were not doing the job for which the ranchers paid them - namely, to improve and maintain the grazing capacity.
These nobs have no common sense and usually zero experience in practical range management - BUT they love to throw their weight around, forcing ranchers to follow their idiotic directives. They especially love to cause financial damage to hard-working cattlemen. This case sounds very familiar to anyone who has delt with them regarding such matters.
The people in the East and urban areas in general don’t understand this.
The old expression for Nevada’s counties, even Clark County in its old days when Bundy’s ancestors living there had virtually no neighbors, was “cow counties”.
It was all about cows and cattlemen, ranchers if you will.
People living in retirement, casinos, hotels, etc. weren’t there.
Federal bureaucrats weren’t around, ‘managing’ the land.