@mossylog of course some dogs are more capable of causing more serious injuries/killing due to their size and their musculature, but there are plenty of examples of smaller breeds who have given people permanent scars or maimed people or other animals.
As I said, if you look back at the majority of dog breeds, most had jobs to do. It could be hunting, ratting, shepherding, guarding, tracking etc, but those breeds over many many years have been honed to specialise in the tendencies and traits needed to excel at those activities. Then stupid, greedy breeders come along and start corrupting the breed standard, fuelled by uneducated owners who have no understanding of the nature of the dog they are buying and what they need to become happy, well rounded dogs. And we’re all shocked at the outcome?
I own 3 large dogs. 2 are Belgian Malinois, a breed used by special forces, capable of parcouring vertically up the side of a building and defending rhino from poachers. They are far from ideal house pets. My other is a Turkish Kangal, a breed used to protect sheep in the mountains from wolves and bears, with a more powerful bite force than a lion.
I know what I have and it’s my responsibility to the dogs themselves, to me and my DH who live in the house with them, to my family and friends who regularly interact with the dogs, and to any other people or animals who may cross paths with them, to ensure that the environment I provide gives them the fulfilment they need in all aspects of their life so that they remain healthy, happy and stable.
If all owners took their responsibilities seriously, we wouldn’t have half the issues we have today, with any dogs.