Properly socialized their dogs from a very young age, got appropriate training, are bred by responsible breeders, and most importantly people learned dog body language and respected it. Many bites with children is because they don’t respect a dogs space and the dog reacts like any of us would if someone is all up in our face bothering us. We expect dogs to just accept that behavior from us and not defend themselves.
Anytime I’ve been bitten grooming dogs is because I missed or ignored their body language. Now that I’m very proficient in reading their body language, I know what dogs might go for a bite and usually avoid it.
I wish I was good at public speaking because I’d love to go around to schools to teach kids dog body language and how to be safe around their own as well as strangers dogs. I think it would be effective in preventing many bite cases if both children and adults were taught this. For example many people think an upward wagging tail always means friendliness or happiness, but it’s way more involved than that. There’s many different types of tail wag and reading the whole body with the wag is critical to understanding what the dog is feeling.