They also are rarely serious bites so I'm not sure what point you're making

The point I'm making is that the framing of bully type dogs being more naturally aggressive or violent than other breeds is not the case.

they care if a dog mauls their toddler to death - which happens with far too much regularity

These deaths are tragedies, but are not regular. The reason they're newsworthy is because of how rare these events are.

I think a large problem with the narrative around dog breeds, and their associated traits, comes from a lack of education and understanding about breeds and traits. You're right, certain breeds have been selectively bred for certain activities: what this means is that collectively, dogs of this breed respond positively to being trained for that particular activity, as well as having physical characteristics to advantage them for that activity. It's not that all dogs in the breed are predetermined to show those breed's traits.

For example: border collies were bred as working dogs, specifically for herding sheep. Some have an innate herding instinct but generally they need to be specifically trained. A friend of mine had a border collie and it was the laziest dog in the world: it had no interest in herding or doing trial training. You can't assume a dog from a certain breed will display the generalized behaviours the breed is bred for.

It's telling that the biggest dog charities in the UK oppose measures for banning specific breeds of dog, because it does not work and takes attention away from measures that do improve safety, like responsible dog ownership and training.