I'm very much on the fence about this because I am very much that it's both owner and breed.
There is no denying that breeds have traits, I'm a cat owner and if I get any more pedigrees I will be looking at the more energetic outgoing breeds (Siamese, Bengals) as opposed to the quieter breeds (Birmans, Persians) because whilst there is never a guarantee there is a high chance your cat will conform to breed standard if you get them from a responsible breeder.
I'm also very much of the belief that ownership has a lot to do with it too. If you neglect a cat then there is a chance it could end up being aggressive even with proper breeding.
This is also where it goes hand in hand.
Let's say I'm looking for a first generation Bengal cat, only one step down from being half wild the chances are I will end up with a cat with wild tendencies who will need a lot more care than a Persian. I do my research, go to a proper breeder and take care of my cat correctly then there is a high chance I won't get my face ripped to shreds but with their breeding it's more likely than something like a Persian.
If I don't care where I get my cat from, choose any old breeder, don't look after it properly then the chances of it ripping my face to shreds is higher than the above scenario and again higher than a neglected Persian.
The problem with these dogs is that all of the above applies but the breeding is problematic. A bull breed was used to bait and fight bulls/bears/each other and so the breeders would breed the most successful ones and so the temperament would be passed on. A Staffordshire Bull Terrier also has terrier bred in, a fiesty temperament bred to dispatch rodents in a swift manner. So you have 2 breeds designed to kill mixed together so not ideal. I've no idea what am
The size again causes more problems, a dog the size of a pomeranian couldn't kill someone no matter how hard they tried but the size of these, their tenacity and willingness to fight is a terrible combination.
If Owner A chooses a reputable breeder, one who breeds for a friendly temperament and health then the risk of them attacking is low. If they do everything right, train them, don't let them be alone around kids/new people then the risk is lower still. Never zero because there is always that potential in any dog.
If Owner B chooses a dog which is bred by someone who doesn't care what the temperament of their dog is or they choose one for their aggression then the situation becomes high risk. If the owner never walks them, socialises them, trains them and neglects them then the risk is suddenly a lot higher.
Now I don't know enough about the breed/breeders to say if there are responsible ones but the stories coming out of the media suggest they are not because they are being sold to people with unsuitable circumstances and then a lot of the time passed from pillar to post. A responsible breeder should be willing to take their puppies back, help with rehoming, not sell to people they suspect will breed from them willy nilly. These dogs seem unsocialised, overcrowded, untrained and not exercised so it's a lethal combination and people are paying with their lives.
I agree with the ban and I don't agree with it. I agree with the premise of trying to reduce the risks and helping cull the irresponsible owners to an extent. There will always be those who don't listen just like there will always be murderers and thieves. I don't agree with it because ultimately it seems people are responsible for the outcome. Ban these, reduce deaths, great. Some other dodgy breeder will start to put the wheels in motion to create something else to sell to people who mostly want the dog to give off the "don't mess with me vibe" and so eventually the cycle begins again.
The only answer is to have a total crackdown on dog ownership. Dogs of all breeds bred properly and sold to homes of high standards with official paperwork. Vets to go through the paperwork of any new dog brought in and report and have the power to seize any that don't seem legit. Those found to not be need to be PTS, even a pomeranian and owners given a fine.
Obviously there are still massive flaws with this, one is money and time, there aren't the resources. Two it won't stop people from going underground, it would stop people seeking treatment if their "underground dog" was unwell and ultimately an innocent animals suffers. There are probably a ton more flaws as well, I'm thinking rescues, in breeding but I can't really articulate what I'm thinking.
So really since the "answer" won't happen I don't know what the solution is when we don't have the resouces. I do think the government despite my dislike of them are trying to mitigate damage and doing the right thing, it won't stop attacks but maybe it might reduce the numbers because they are harder to get hold of/harder to have unregistered and thus reduce the attacks.
I do question why anyone wants a breed known to have killed several people and also question the suitability of some breeds to owners. I wouldn't choose a large guardian breed in my small suburban home, I would go for a small companion breed but if I lived on a property with a large amount of acres and livestock to guard I would be more likely to consider a guarding breed.