I used to walk my brother's Irish Wolfhound (almost 200 lbs), and the neighbour's Chihuahua would scare it......they are brave little dogs.
The attack in the link is horrible: I hope the offending dog owner is punished in some way (but it does not sound like he was).
And I hope the little girl is able to fully recover....she appears to have some serious injuries.
As far as Pit Bulls (or Bull Terriers), I lived next door to one for years.
My young kids played with it all the time. But it was raised by a kindly, little-old-lady.
And of course, "Petey" on the Little Rascals was a Bull Terrier.
I agree 100% that the offending Bull Terrier should have been put down, but I really blame the fact that the owner probably "trained" it to be vicious.
I'm pretty sure you could get a Beagle to act badly if you raised it to be that way.