Well, now it is clear why the Sheriff is on the side of the Feds - He used to be one:

http://theconservativetreehouse.com/...-story-hidden/
Sheriff David Ward formerly worked for the Federal Bureau of Land Management and appears to have actually been a witness against the Hammond family in the ridiculous federal terrorism trial back in 2012.
Obviously, now that “Rangeland Specialist” Dave Ward is now Sheriff Dave Ward, he would not want the larger public to understand his complicity in the prosecution of the Hammond family. Nor would he have any motive or intent to protect Dwight or Steven Hammond from the appealed second set of sentences which were demanded by activist U.S. Attorney Amanda Marshall.
Small town corruption.