- I would wager that a Chihuahua is less likely to kill an adult human than a Bullmastiff, just because it is less capable of it. - Many small dogs, in general

- I would wager that a Chihuahua is less likely to kill an adult human than a Bullmastiff, just because it is less capable of it. - Many small dogs, in general, are poorly behaved because you can just pick them up and move them instead of having to train them. - People also make sweeping statements about breeds like the American Pit-Bull Terrier when the variation within the breed is very large. - If I'm an asshole who's going to train a dog to be aggressive I'm going to pick one that looks scary. - Selective breeding within a breed can change temperament as well. - Banning individual breeds is stupid whack-a-mole. People will just pivot to a different large-dog breed. - If you want to make people not use dogs as weapons, about your only choice would be to ban dogs over a certain weight. This would almost certainly ban e.g. Bloodhounds (males commonly exceed 100lbs when at a healthy weight) though so isn't going to happen.