eb30 responding to your post,
while I agree that they have been bred for that purpose and the instincts were bred for as well, I do not believe that that is the last word in behavior. Dogs act like dogs first, before breed behavior. My point is that as dogs they must be properly socialized trained and be taught to be submissive to their owners and other humans. Many people I have met who have dogs any kind of dog do not take the time or have the knowledge to do these things regardless of breed. Often owners simply leave their dog at home only walking it for a short time each day if the dog is lucky. You can't do this with a high energy dog intelligent dog (well maybe a lab), not really the way to treat any dog though. Think it's the breed problem, then think of the spoiled overprotected chihuahua, daschund, poodle, terrier, etc. that I'm sure you've experienced, that becomes overprotective itself. No one says anything because it's not likely that one could kill you or even severely injure you.
Dogs need to know what is a threat and what isn't and how to react properly to different situations, they can't get that by staying home. Dogs need to learn these things early by proper exposure and training. The problems are worse if a dog is allowed to feel dominant to their owners.
But in regards to trends, there is a clear change in "dangerous breeds" as one tough dog fad changes to the next. In the '70s as the writer pointed out '72 to be exact the Doberman gang was released, and instantly the Doberman became the tough dog, this lasted into the 80's as movies such as Magnum PI and others such as the media continued to portray the Doberman as a vicious dog. In the '90s the tough dog to have as an ornament in the back of your pickup truck was a Rottweiler, and about that time too, the Pittbull was picking up in popularity as it was portrayed in hip hop culture and even the news report of attacks promoted these dogs as "the" tough dog to own. Also as the numbers of a breed increase because of popularity the number of bites will should increase too due to simple probability. Pittbulls are more common now then in the 70's and Dobermans are less common, so stands to reason simply based on that the bite numbers for the breeds would change.
So why do people want the "tough dog"? Ego of course, besides believing it makes themselves look tough, or feeling they have a weapon in their backyard (these owners actually want a dog that would attack people), or it's the idea of being able to tame the urban equivalent of a lion. Ego is not always bad either, and doesn't always make the owner a bad owner, nor am I saying that all tough dog owners have their dog for ego inflation, but many do. People need choose a breed base on compatibility with their lifestyle compromises they are willing to make raise a dog, and not based on which dog makes them feel tougher, cooler, more attractive, etc. Tough breeds and working breeds often need a lot of exercise and mental stimulation for them to relax properly and be happy, if you can't make that commitment, then maybe it's either its time to look at other breeds or maybe get a plant. Dogs make a horrible fashion accessories.
Doing sudoku with my daughter.