This is so sad in so many ways,
Im a dog owner, my rescue is a very anxious dog so we walk her when its quiet and with a muzzle. I avoid people so she cant scare them sometimes she does bark and her buddy Rolo backs her up, I always tried to keep her contained so she can never hurt people although to her its alway offence more then defence.
Big dogs especially those who can be aggresive should have been leashed so they couldnt hurt those people and other dogs, but its still someones dog and if it were ours, part of our family.
And that poor dog my heart goes out to its owners and their injuries