If a child is harmed because their parent allows them to approach and torment an unknown animal, as far as I'm concerned that is the parent's fault and they are negligent. No responsible parent would put their child in that situation.
What do you mean by ‘tormenting’? Most children don’t intend to cause distress to a dog, they’re either too young to understand you shouldn’t approach a dog or they don’t realise some dogs startle and snap.
IMO it’s ALWAYS the dog owner’s fault and lack of responsibility if a child gets bitten in public. If your dog is nervous of children and likely to snap, you muzzle it. I say that as a dog owner. My large breed is fortunately well socialised with children and tolerant. But I’ve lost count of the toddlers and just-walking babies who’ve tottered into him, stepped on his paws, grabbed his fur. A small child once tried to climb on his back while we were in a queue, another time a baby leaned out of a buggy and grabbed his ear on the bus. It only takes a split second for a parent to look away and an infant to grab at your dog or walk straight into it.
Any dog taken to a public place un-muzzled needs to be unflappable and trustworthy around small humans. Because… children take priority over dogs.
There are no requirements to have your child on a lead in any place, there are no parks or beaches with child bans. Kids may be clumsy, impulsive and inquisitive but they don’t attack people. Even if someone startled them or trips over them, no child attacks out of shock/fear/rage.
Most parents I know and see are responsible, they teach their children how to behave around animals. But some children are too young to understand/remember, or have SEN, or simply forget to look out for nervous dogs when they’re running ahead or playing together. A parent can’t have eyes on constantly, even a helicopter parent can get momentarily distracted.
A child who is harmed by a dog in a public place… do you really think it was the parents responsibility for letting them approach an unknown dog? Did the parent even see the dog, or predict their child might try to touch it?
Public spaces are supposed to be safe for children. Bringing snappy, poorly socialised dogs into these spaces is asking for trouble. As a dog owner you’re responsible for your dog’s behaviour.