First, if you want to be accurate, ALL terriers were designed to kill. Some for rats, some for foxes, some for other dogs. Modern life and selective breeding has dulled the instinct in most lines though. I haven't met too many Daschunds lately that are capable of taking on a badger in its own hole. You do know that St Bernards are consistently on the top ten "deadliest" dogs list right? They're large, extremely powerful dogs that are more then capable of delimbing you. I'd say a full grown Bernie has a much better chance of doing that then my 43# Stafford. Sure, there are lots and lots of stories about pit bull attacks; mainly, because it makes for a sensational story. Pit Bull Attacks Honor Student sells more papers then Jack ass Kid Hops Someone Else's Fence, Gets Chomped by Lab/Vizsla mix
Fully half of the scraps my last dog got in were with intact, male Labs. People buy them thinking that they're great with kids and other dogs automatically. Then they don't socialize or train them. ALL dogs need socialization. My Corso (a very large headed, big, muscley, scary breed) had his CGC, TDI, and TT certificates. My Stafford will likely never test for any of them. Is it because he's too dangerous to take out in public? No, its because he's too overcome with joy at meeting every stranger he sees to stay sitting without a leash on for more then a few seconds. Its embarrassing at times. Bull breeds are the AR-15 of the dog world. There are more of them then pretty much anything else, and they're usually demonized more because of how they look then any for any other reason.