Training goes a long way. Yet my experience with dogs is that there are individuals with a bad temperament. And breed does strongly correlate with size. So in situations where a bad mannered individual dog of a large breed does act out the potential for harm is higher than if it were a smaller breed.
Owning large and powerful dogs of any breed is a risk.
> Owning large and powerful dogs of any breed is a risk.
Pitbulls aside, anecdotally, if we're talking breed size I've found Pomeranians and Jack Russells to pose more danger than, say, collies, labs, Great Danes, Newfies, etc. but I guess now I'm the one generalising.
I think training and care are really the main factors. There are certainly cultural tendencies to apply certain training approaches to certain breeds, but I really do think this is mostly correlatory.
Specific dog breeds do tend to exhibit behaviours naturally associated with that breed but if you're going to own a dog, look after it. That's all. Making generalisations about breeds needn't override that.