I agree that the prosecution overshot the mark as far as "throwing the book at them". Calling the defendants "yahoos" was apt so far as it goes. but it would have been more dignified to link the usurpers to the old and widely influential sway of the posse comitatus movement, an anti-federal movement begun as a quasi-legal opposition to post-Civil War reconstruction and morphing into Jim Crow laws and crimes.

However, I believe the larger point is in the legal sanctity of property rights and the duty by law to enforce those rights.  In this case, as you say, it was not deftly, or even competently, done by the prosecution.