I’m talking about the moral responsibility of the owner. He created the stage for a tragedy.
1) Don’t get a dog if you’re going to chain it.
2) Don’t get a dog if you can’t provide a safe fenced home.
3) Don’t get a dog and leave it unprotected where other dogs can get it.
The owner was acting responsibly; the dogs were contained, until they, enraged by an canine intruder, pulled free by slipping a collar and breaking a chain.
This was a matter for catch poles, and perhaps a fine delivered to the owner for failure to anticipate the growing strength of her dogs and provide a tie-up strong enough to keep a fully grown mastiff contained. Not a shooting.
As has already been mentioned, having a fence on one’s property is legally impossible in some areas of the country. You would deprive Freepers living in those places of the excellent first alert service that a good watch dog provides when the criminal element (or bad cops intruding on private property without just cause) come lurking?