This mantra that it's just the fault of lack of training is specious. You cannot train an attack dog not to ever attack. They're bred for aggression and this can't always be suppressed.
"This genetic history is present in the XL Bully. “These dogs, being bred for aggression, are likely to inherit aggression,” says David Sargan, a geneticist at Cambridge Veterinary School. “However well you treat them, a proportion of them may explode.”