Arson/felony has several conditions; I don’t how they apply to machinery, in what degree.
Barr can not do anything unless it is a federal crime.
So far not a single poster has any clue as to whether it is a federal crime.
Many a farmer has suffered much worse because he put up a fence on a disputed property line... including murder.
So the equipment could have been burned for many reasons besides politics. Fence line, loose cattle, farmer's daughter, dog, local politics, or just pain meanness.
None of which is any business of the feds.
I am as conservative as anyone and much more than most, but before one rants one should wait to learn the facts.