As far as I understand, that comes from having bad experience with dogs. So for example, a dog was exposed to another dog and the other dog spooked your pup somehow.
I would tend to agree, except the reactionary tendencies were pretty exclusive to breeds that had strange faces (pits, pugs, etc) or that looked very dissimilar to what he'd been exposed to. Who knows? *shrug*
These dogs are very small, and not especially well trained. They're very sweet, trustworthy. Just not well trained. They kind of do what they want because they're little. I may be a little afraid of the bigger puppy hurting them... We had a Jack Russel several years ago, and our puppy at that time's favorite thing was to try and squish her with his huge foot. :/