In this case, the boar concerned is apparently a sow with dependant young. Killing it will mean only one thing for its family. This goes a long way to explain why the boar acted as it did. It's a trait common to all species - that of the instinct to survive and to protect the survival of it's offspring. A dog would do the same thing if a boar came bounding in to an area where it was caring for it's puppies. It's instinctive.
Wild boar will not attack unless provoked. I'm yet to hear a believable story of a boar attacking a human. When alarmed, a boar will make some incredible noises that could easily be construed as aggression. It will then generally run away. If you're lucky, it may even approach you for a better look (their eyesight is poor). Whilst taking these photos, and on many other occasions, I have not had any cause to fear for my safety. However, a determined dog could keep up with a fleeing wild boar, and to the dog, the piglets no doubt represent something perfect to play with/eat. This is provocation in every sense of the word, and we can't be outraged when a boar responds in the unfortunate way that it seems to have done on this occasion, much as we do have every sympathy for the suffering of the dog and the anguish of its owner.
The wild boar live here. Apart from a prolonged absence caused by man's hunting to extinction, they are back where they have always lived - they belong here.
I'm now a dog owner too. I hope one day to be able to let her off the lead in the Forest too. However, that will only be in areas where I know the chances of encountering wild boar are close to nil, and only then, when she has suitable recall control. Until then, she goes on the lead, and she goes to other places where she can safely run free.
This newspaper article, assuming it's accurate, makes it clear that the owner knew there were boar around. I'm a dog lover, so I'm truly sorry to hear what has happened, and I hope the dog makes a good recovery. However, this wasn't the fault of the boar, nor of the dog. Both were doing what comes naturally. We have very few creatures in this country where care needs to be taken for the safety of pets and ourselves - other countries have far greater, and far more real, dangerous creatures to deal with - they've adapted and learned to live with those creatures, and so should we. In this particular case, it's not actually much to learn to live with. Most people in the Forest have never seen a wild boar, and if it weren't for these stories in the media, they would barely know they were here. The Forest is still a safe place for people and dogs to be. There's every chance that public understanding of the boar in Britain is less now than it was in medieval times, and that needs to change if the wild boar are to stand any chance of long term survival here.
Thanks to Rob for the image of the newspaper article.