These dogs are used as weapons, they are not pets. I would less afraid of a gun, at least a quick death and more accurate, without seeing a toddler mauled to death.
I've been attacked by a dog twice, once an idiot owner, German Shepherd had gripped my arm, owner who was watching said he was playing, big bite force and still wouldn't let go of my arm. Didn't try to drag me to the ground though.
The other time a feral dog in dog in Italy. Not only grabbed my arm but tried to get me on the ground. Fortunately had a coat on so not bitten. Very strong though.
Had two pet rescue dogs as a child, first was aggressive, eventually put down. Friends wouldn't visit. Dad would randomly resume these dogs and then have nothing to do with them.
Second was lovely but didn't like men, from the word go, very protective. Would need to be carefully introduced to boyfriends, he would growl if they touched me. He was lovely with female members of the household but eventually re traumatized by my dad. Heard him being beaten up. He wasn't really the same after that and would snap, needed to be kept on a lead, bit me when my face was close to his. He was always on a lead around children as they were at face level. I think he had his issues to begin with, but could have been a lovely dog. He wasn't an aggressive breed, but possibly some collie there?
Personally I would vet any dog around children, and teach children not to approach dogs they don't know. Plus teach keeping your distance for family dogs and boundaries. Phrase it as they'll, the dog, might be scared.
Rescue dogs in particular can have a history. Great niece shares her home with a lovely Labrador, bought when he was a puppy.