It all sounds like the behaviour of irresponsible dog owners to me but again, why should the dogs pay the ultimate price?
What about an annual Mutt Owners' Test, MOT, to prove that at licensing time, owners and dogs behave in such a way as to be safe to be out in public together? Proper dog retraints, leads, muzzles, proper ID tags, (FIDO registrations), chipping, etc, and behavioural testing with specialist dog trainers.
Killing animals be they domestic companion dogs, wild badgers, seagulls, foxes, or deer is not the appropriate answer in a civilised society.