Having been 'in' dogs 50 plus years running training classes, offering help and advice on training and behaviour my own opinion is that these dogs are of no good as a pet and have no traits of 'working' they are bed to fight and kill each other, kill other dogs and even people. They are owned for the most part and bed by people for money and have no regards for the welfare for the dogs, other people ot the law.
A ban will push it under ground and the cost of pups will rise and these people will just breed something give it a new name and carry on.
If you could enforce a law (won't happen not enough cops) that these kind of dogs had to be muzzled in public areas and no one could walk more than one it would help. People seeing a muzzled dog will avoid (for the most part) it, when in fact it's the only dog that can't bite you.
Have a look at my website www'cceg1.co.uk
It's people who let dogs down.
Dog Training - Gentle in what you do, firm in how you do it.