My take is it's a left-wing couple with a neighbor that they knew had guns and was probably right-wing. Their lives likely quickly began to boil down to nothing but bullying and tormenting their neighbor whom they perceived as "sub-human racist, nazi, sexist, pig" because he was a gun-owning american. Cops do nothing for shit like this and it's possible this couple were digging into this guy for months/years. Think about it, they picked up snow from their property and carried it across the street to throw onto this guys property.... sound like reasonable people to you? The guy come out with a gun and they still keep spitting in his face, they had no fear of this guy. Which is another symptom I've observed in the deranged left, which is that they never think of any consequences. They'll take a piss on you every day and will be absolutely stunned by so much as a literal slap in the face.