I can't quite believe this spin, let alone that you're actually being ernest.
Really? The mother should have put down the phone, so that in the event of either the horse or themselves being harmed by a dog with zero recall, training, or ability to stop attacking, they would only have their word against his as to what happened?
Stuff that. In any event, I'm sure she would have put it down had the dog directly come for the child.
Thankfully this man and his animal were filmed and the locals, including those with children in that area and neighbours living next to him (pity them) know that this dog owner has no control over his animal. They can thus strive to avoid him. If he's out in a public area with his dog unleashed again and there's an incident someone can contact the police who now, thankfully, have ample proof that the owner is irresponsible and incautious and can confiscate the dog if necessary.
A horse is a big powerful animal. The rider prevented that dog being kicked or trampled to death, the dog owner should actually be grateful that she had such great control of the horse.
A jogger, cyclist or child on foot would have had no chance with that dog. You can clearly see a grown man has difficulty managing him.
I can't believe you think the parents response to the child's distress is just clickbait material.