I am not a fan of Staffordshire Bull Terriers at all - don't see the appeal of them myself, and I personally would never choose to own any dog whose breed was originally developed for fighting or baiting, and I question the motives or judgement of anyone who does. However, I am aware that they have been a very popular breed for years with very little bad press at all - until they became the latest status dog of choice for knuckle draggers and people with violent/criminal tendencies.
The trouble is, what most of these people really wanted were pit bulls, but a) they are banned, and b) they were pretty hard to come by. Breeding more muscular, more aggressive strains of SBT has been a way to emulate them for many.
But breeders have worked on crossing Pit Bulls with all/any of the other bull terrier breeds, also mastiffs, and American Bulldogs and have come up with all sorts of smoke and mirrors schemes to basically sell dogs that are 9/10ths pit bull, or pit bull crossed with staffs, or mastiffs, cane crosses etc, to get the biggest, baddest dogs, chockful of fighting genes, that they can produce, but always managing to dodge regulation and the dangerous dogs act, by saying they are not 'pit bull types', or banned breeds, but 'staffies' or bull mastiffs. And they are selling dogs which are to all intents and purposes Pit Bulls under code names like 'American Guard Dogs' etc. The internet is full of them if you know what to look for.
Certainly Bull Mastiffs are no angels, despite what their devoted owners will tell you. The people I have known who have kept BMs have been the sort of people you don't want to accidentally bump into in the pub iykwim, so let's say it's no coincidence they don't own poodles.
It's extremely hard to be exactly sure what breed some of these dogs are, or are not. And my guess it that hundreds of thousands of dogs are going under the title of 'Staffie' in this country when actually, they are not pure Staffie at all. They are at least part banned breed, and the owners know it, but won't admit it. But there is little doubt they have been breed to be strong, brave, intimidating and fiercely loyal. In other words, weapon dogs that they think will give them added gravitas.
I have only ever known of three people in my aquaintance to be attacked and injured by dogs.
One was about thirty years ago - my then boyfriend's aunt took on a pit bull type/American Bulldog puppy from a rescue. This was before they were very well known, and before the ban. She had to have it destroyed at about a year old when it attacked her and she ended up with a face full of stitches and not much top lip left.
The second was a friend's 2 year old nephew. They went on holiday and stayed in a hotel where the owner's dog was a Bull Mastiff. It savaged the child in a totally unprovoked attack as the family all sat eating a meal in the hotel garden. The child underwent emergency surgery and the dog was destroyed.
The third was my friend's daughter who owned an Akita. Despite being trained in dog handling and animal behaviour, it still attacked her and she had to have it destroyed.
I've seen the photos of the dogs in this recent attack and not one of those dogs looked like an actual Staffordshire bull terrier to me. Two were bull mastiffs and the others looked to be of a pit bull type. Although they may have 'officially' been staffie as far as the owner was concerned. 
Whilst I agree that the problem lies probably more in nurture than in nature, I do think that some breeds are more predisposed to attacking and fighting than others, and when under stress or in a pack, are more likely to revert to type. Especially if they have been poorly handled by fuckwit owners. And no-one will ever convince me otherwise.
I agree that any breed^ has the potential to turn nasty and get a bad reputation en masse, if enough irresponsible, dim, or downright nasty people buy them. I agree with what DoinMeCleanin said upthread - I think the next status dog to go bad will be the Husky, Malamute or Akita. And it's no good saying 'oh but daschunds and chiahuahuas and Jack Russells are really unpredictable and aggressive - yes I believe they can be, but they are about this > < big, so.... 
But I also think that until macho, wannabe gangstas with small dicks and even smaller brains want to start dragging Golden Retrievers or Cocker Spaniels around with them while they patrol their manor, (or is it hood these days?) we are ALWAYS going to see a disproportionate number of attacks by Staffies, Staffy-crosses, pit bull crosses, Bull mastiffs, or any other breed that was originally bred with fighting or baiting in mind. It is not a coincidence that the wrong kind of people pick these dogs, is it?