I own and fly quads. I'm usually flying to get images/video of buildings, architecture, and land. Large object that film very well. Not people.
hobbyist "drones" are loud and are not good at spying on people.
If the shooter had gone and talked to the drone owner, he would have seen what limited view the owner has.
In general, the shooter is in trouble for shooting a gun, not damaging the drone. If the drone was down at 10 feet, then you would be within your rights on your own property to toss a net onto the drone. Maybe you could use one of those air cannons that shoot shirts. Again, if the drone is within range of that, then I highly doubt you will be arrested and/or charged for firing it.