There are dangerous dogs and dangerous dog owners. I have drafted a Model Dangerous Dog Owner Ordinance. It identifies dangerous dog owners and creates penalties for them. Among other things, they can lose their dogs. While that would be harsh if imposed on someone who loves their dogs, it is an appropriate remedy against irresponsible dog owners who make their communities unsafe or unsanitary.
Dog owners have to fully understand that their actions usually are the cause of a dog being dangerous. No matter what breed of dog is involved, a dog can present a substantial danger to one's family, friends and community if the dog is mistreated, not cared for properly, not socialized, chained, injured or ill. The responsibility for all of these conditions is bourne by the dog owner, harborer or keeper (except for temporary keeper). A breach of one's duty toward a dog can result in tragic and even fatal consequences befalling a friend, family member or neighbor.
Read the model law at Model Dog Bite Laws, a section of Dog Bite Law (dogbitelaw.com). This law and the other model laws should be enacted in every community. If yours does not have these laws, you should contact your local and state representatives and tell them that these laws should be passed.