Many years ago, there was a big blowup in Germany over a GSD male that killed a child. It was all in Stern magazine, which is / was big at that time. The child was very small.. 5 or under, and went (unwatched) into the dog's kennel. Easy to understand the reasons it could have happened, if you know dogs.. territorial drive, etc. But, the public doesn't understand dogs very well, so it's easy to sensationalize something like this.
Also many years ago, I got messed up pretty bad by a GSD male named Ufo vom Fiemereck. I was crazy to buy that dog. He'd already put several people in the hospital, some with serious damage (disability, disfigurement). Well, the things I didn't know about dogs got largely filled in by Ufo. Let me tell, you, also, that I got my licks in and survived the attack.. Then went back later and kicked his ass with such excellence, that he knew he'd seen his Waterloo. From then on, he lived by MY rules, and he behaved. Come to find out that there was a crazy streak running pretty wide in that particular bloodline, and this came to be pretty well known. The bloodline was pretty much abandoned by Martin Steffen, even though it had brought him a lot of success in the show ring. Whatever remains of it is VERY diluted and buried in pedigrees, by now. I did have pups from Ufo and they were mad as a hatter, by the way. They did some really crazy, feral stuff.. in Ufo's case, the problem feral behavior was extreme social behavior, on the alpha side of the scale.
Anyone who trains dogs and really knows what's happening in their heads knows that they can switch drives really fast, and they "throw" behaviors (see Karen Pryor). So, lots of things can happen and the average person has no idea why the dog did what it did, nor what to expect of it. People see dogs as "furkids", and expect them to behave rationally and morally. Konrad Most said that by placing the dog into the realm of moral expectations, that we do him the greatest disservice. We set dogs up to fail, so we should not wonder when they do fail. A dog cannot truly understand the concepts of right vs wrong, or what we want, or why we want it. Owning a dog is a lot like having a two or three year old child. We have to constantly work to keep them out of trouble.
The whole thing with Pit Bulls is the immense popularity of the breed with the least responsible people. They are the dog of choice for wannabe and real thugs, dope dealers and just general dysfunctional people. Their numbers are huge, and that right there tells you that the odds are against their reputation, statistically.
The other strike that Pit Bulls have against them is their long history of breeding as a butcher's dog and later a pit fighter.. giving them tremendous grip and gameness, as well as physical strength. A bite is often a bite and hold, along with shaking, which can cause tremendous physical damage to the human victim. To a bull, with a tough hide, this would be sustainable, and we would praise the dog for hanging on while the bull tosses him in the air, giving the owner a chance to escape the bull. There is a video showing just such an encounter on YouTube, and the dog was a hero.. probably saved a man from death or serious injury.
This is a great breed of dog with the odds tragically stacked against them. If it weren't for the huge popularity with responsible owners (who fight like hell to protect them), they would be doomed by rounds of yellow press journalism and legislative efforts to eradicate them.