Your three data points don’t nullify the larger pattern. Lots of dogs can be shitty. Pit-bulls are uniquely strong and aggressive though. And German Shepherds can be gnarly bastards too. They’ll all fine if their owners know what they’re dealing with and can physically restrain the dog, but that’s so often not the case and owners don’t realize how little control they actually have until their dog is already gnawing on a child’s leg.