I can find you a lot of anecdotal cases of it happening, although I'm not aware of any studies that specifically look at that.
Even if I'm completely wrong (I'm not), why though would anyone be against mandatory spaying/neutering and a ban on breeding, on a type of large dog that has a very high chance of being specifically trained for brutality due to human attitudes anyway?
Either way, once you see one of these things drag down an adult human, you no longer care about the why, you just accept that they need to go.