Terrible, terrible tragedy. Poor family.
I don't know about this particular case so am not commenting on these specific circumstances, but rather am talking about the general dog-owning idea when I say......
The problem is, people do love their pets so much and see them as a family member. I realise that the idea of loving your pet does not instantly appear to be a problem..but if you fuss and slobber over your pet and make it feel top of the pack and don't keep it in its place (the bottom and grateful to be there!), it can create problems.
While there are many very good dog owners, who do everything right, I do think there are also a lot of totally untrained dogs around. I think that really needs addressing. If you are going to have a dog, you should have to ensure it is properly trained, knows its place and is managed properly.
Of course, any dog can turn, but a well trained, well disciplined, properly handled dog is probably less likely to do so.