The dog isn't the problem. Dogs are dogs.
Fuck that. For example, in my new neighborhood there's a couple doberman's a few doors down, and the idiot owner lets them roam the streets by themselves. Aside from the doberman's, my dogs are the biggest and strongest in the neighborhood, so naturally the four don't get along very well.
My dogs aren't allowed out on their own, but if for whatever reason the 4 of them end up on the street by themselves, guaranteed a fight will break out, and the doberman's are capable of kicking the shit out of my dogs. If that happens, I'm not going to have a problem taking a baseball bat to the doberman's. If the owner gets pissed at me, fuck him for letting dogs like that wander the streets by themselves.
Same as I've had to take a broom handle to my dogs before at my old house. A new dog moved into the neighborhood, and was bullying the pups next door. My dogs didn't appreciate that, so took after him, and without question were going to kill that dog. I freaked, grabbed a broom, and started smacking my dogs with the wooden end of it, to get them off that dog.
It worked though, and the other owner thankfully kept his dog inside after that. So that dog got to live, and the pups were allowed to play without getting bullied.