It is as simple as this. There's nothing, really, to "get". This movie is about freedom and peace. It's about how the tyranny of the "Status Quo" stifles the spirit of man, and with bleak outcome, illustrates how this wreckless hatred of difference, and unacceptance of our fellows, ends in destruction of peace. Those with baseless pride, always quick to judge and condemn, are the real villains, despite the protagonists' lawlessness, they bring no harm to anyone, which is in stark contrast to the majority of those they encounter.
I keep reading reviews on how many "sided with the rednecks". All I can say is that if you find yourself doing just that, then you really must delve further into the nature of freedom. *REAL* freedom.
That is the essense of this film. It is the one word of description to label it and define it. The protagonists' are on a quest to discover what it is to be free, whilst indulging in it. The realisation of the farmer's existence is an example of where they see how freedom is manifest in different forms. Despite the choice of the expression, the farmer and the (anti)heroes share a similar viewpoint on life.
This may very well be the most patriotic film ever made. It is a shame that so many can't look past the surface to see that fact.