That's the point, young dogs of sound genetic temperment frequently make incorrect decisions about what is and is not a threat. It's up to the OWNER to help them learn the difference, WHILE ensuring that NO ONE gets bitten innapropriately!And IMHO, you are dead wrong? A dog that has bad nerves, genetically, and misinterprets a non-threat as a legitimate one (such as in your example), very well COULD bite in the wrong situation, regardless of training, and it has very little to do with the owner, but more so the inherent genetics of the dog itself.
(Or is EVERYTHING I've read elsewhere just totally wrong, and this place - and the people in it with their "opinions" - is just the end all, be all of German Shepherds?)
Your dog is fine, your management of such a young dog just needs to ratchet up a notch or three - especially if there are kids in the neighborhood. Come on dude, I wasn't attacking you, just stating the obvious!