Sadly, people working for the government have a long history of immorally, and sometimes even illegally expanding their power and authority.
You can find many examples, over various administrations of this happening. It's not just a REP or DEM thing.
Look and see how people who own land, in a place the government (or more correctly someone in the gov) want to add to their holdings.
Legal harassment, charges, sometimes even convictions, raids and in one case I heard of even what amounted to murder (though it was an "accident", officially).
In the case of the Hammond's, it appears their ranch is the only one left in the valley that the gov has NOT (yet) bought so it could be added to the wildlife refuge.
A lot of people in the west know these things go on. They know it from personal experience (and not just in the west). When some bureaucrat in an alphabet agency decides they want YOUR land to add to their domain, they have lots of ways of making your life miserable, until you finally agree to sell.
Its not right, and it should not happen, but it does, and it is. The Hammond case appears to be one such (if the reported backstory is even remotely true).
The other bunch, the ones using the Hammond case as their justification for occupying federal property, is, in my opinion, in the wrong.
Not all of their complaints about the government's practices are without merit, as I see it. However, real valid issues are being driven under by their extremist stance. I fear they will do more harm, than good, in the end.