There are nuts everywhere.
However, I am sure there is more to this story than just a wee bit of poop.
I think so. Based on info in today's paper they lived above the shooter with a patio above his. They let the dog pee and crap on the patio and every now and then would sweep it off to the ground below, directly in front of his patio.
His solution was still unwarranted, but it sounds like he had reason to be upset.