There have always been GSDs with social aggression and years ago, many more than there are now. It is a required component of fight drive but since so many now seem to lack the basic understanding of what a GSD is supposed to be, ( and some will argue there is no such thing as fight drive), there are topics like the one mentioned on the PDB, questioning why anyone would breed for it. The ignorance in that question is amazing.
Social aggression is not trained and it can be a case where SchH does not put it on display at all. Not the way most of the training is conducted now anyway. Of course, you have to have the nerves to go with this trait, as I have seen dogs who want to protect their person and property and are not accepting of strangers , yet lack the heart and nerve to really follow through when necessary. Mostly, those dogs are defending themselves.
Social aggression, most have not seen, even if they think they have. There is a CLEAR desire in the dog to protect his handler. It is quite obvious and is not "self defense". The property of the handler is also off limits but these dogs can and are VERY good with members of their own family. IMO, this is a part of all of it. The intense bond is part of the protectiveness. The ones I have and do own, are extremely affectionate with me, very good with children and would never dream of biting me.
Civil is maybe what Lee said and goes hand in hand with social aggression. These are dogs who will protect without the benefit of training. It is in their genetics and when the rest is there, have the heart and nerve to take on a man, not just a sleeve.
Most people, believe a dog must be trained to protect. That is just hog wash, although it may be a case soon where that will be required, since so many people do not seem to want, nor do they understand this part of a GSD. A GSD was always known as a dog who would protect. There were not people everywhere training SchH, so, that reputation did not just come from there.
Also, it is extremely important that these dogs do not end up with people who over-react to every little thing. Almost always, it is a case where they show protective tendencies early in their development and this is where living with the right handler becomes very important. They mature in ways that few understand now, since many bloodlines behave like puppies well into their second year. The SA pups I have raised, show protectiveness early and tend to "mellow out" with age. It is just about opposite of what most people are now experiencing with their GSDs.
In that regard, what Hunter just said absolutely applies. Everyone who has trained one dog suddenly becomes an "expert" and they toss out these definitions without experience or knowledge.