They can do pretty decent damage to healthy adults too. I got attacked by a couple of larger dogs a few years ago (technically not pitbulls, but a related breed I'm not sure), had to get surgery and couldn't do my bullshit deskjob for like a month. Any physically intensive job and I would've needed 6 months off work. Considering what dicks employers are I wouldn't be surprised if there are people who end up homeless because someone forgot to close their backyard gate one day.

The worst part is that dogs are pack hunters, so while one dog isn't much of a threat, ten dogs are a mortal danger, especially to children.

I just really don't want my kids around any dogs, which is why I disagree with just letting any of them roam. A dog snapped at my kid's face and now we're both afraid. Dogs just aren't people. They get upset and bite. I don't mind people having them, but yeah.