In my opinion this man has had this happen more than once he walks the same route every day,and this day he decided to shoot the dog.
The right or wrong of it is not the topic of discussion to me, but I do believe he started out this morning with his mind made up to shoot the dog.
Your opinion would imply that he expected the dogs to be running loose.
Then the owner of the dog is responsible. If your imagination is correct, then this poor man is attacked by these dogs often and he finally got fed up.
Plug this into your imagination: if the man walked by the dogs every day and poked them with a stick through a fence, and one day the fence was open, would you blame the dogs for getting fed up with the daily abuse and attacking him?
If similar incidents had previously happened, the person (or persons) at fault are the dogs owners, period. And the shooter was even more within his rights to have taken steps to prepare to protect himself.
My across the street neighbor has a female German Shepherd who is very docile, and a "mop-type" yapper who is very aggressive. Both dogs are allowed to "free run" (despite the local leash laws). The yapper has a habit of attacking people who walk or run down the street, and has bitten one person. I can guarantee that if that little ****** bites me, he is dead whenever I next see him. The Shepherd is a garbage binger, and invariably overturns at least one topless garbage can on pickup day.
Other neighbors have complained, yet these people have taken no action to change things. IOW, they are irresponsible ass holes (and probably voted for Obama).
MY dogs stay in their fenced yard, and only go out on leash.
I get my exercise indoors (treadmill/stepper/weights), but if I were to take up an outdoor run/walk regimen, I WOULD be armed at all times.