Dog Folks is absolutely correct. I've seen many different breeds go on the attack, including my bloodhound, when the situation warrants it in the dog's eyes. And "K9 Special Training" doesn't mean diddlysquat. The dogs I've hunted with in the past have had "K9 Special Training". All K9 translates to is "canine" meaning DOG. A service dog is a whole different story.
I can't really agree with you that no breed bites more than others. There seems to be an awful amount of pit bull attacks.
I sometimes wonder if many dog bites for "gentle" breeds go unreported. While I agree that a rottie or pitbull may do more damage than a collie or Golden retriever, I often wonder what the REAL stats are. Add a hysteria-inducing media and stats get skewed.