Both most owners have no training and I think any time you buy a breed of dog that has fighting dog in it's blood you should have to attend classes. Most of the pitbulls I see are own by some pretty scrappy people. They can't control their own lives and have no business controlling a dogs.
Certain breeds have the propensity to fight, some breeds hunt, some to herd, etc. These instincts are bred into them to improve the breed. I know all dogs can attack but there is significant enough evidence that most attacks are done by a couple breeds.
I don't think any child (or anyone) should have to go through the horror of being ripped to pieces. Don't you just cry thinking of some child calling for their "Mommy" how frightened they are before they die?
You should have to buy a special license for these breeds and have a criminal background check and attend a training class. You have to do some of these things to drive a car, get a gun, get a job. Owning something that can kill something shouldn't just be picked up on a whim with no restrictions.