Why Do Bulldogs Have Flat Faces?

I was perusing the internet one late evening and I discovered that bulldogs have flat faces because it is beneficial in bull fighting. They are supposed to run underneath the bull and its horns then jump up and bite it on the nose and not let go. So they are gripping the bulls by the nose for dear life as the bull whips the dogs around. Now, when the bulldog is hanging on to the bull the flat face allows it to breath freely through its nose, which would otherwise be pushed up against the bulls body not allowing the dogs to or at least hindering the dogs breathing.