Just my opinion, I have a Sport bred gsd, he was socialised very well and trained to a very high standard. You can take him anywhere he is confident, calm and very friendly, I would not trust him with a child for a minute.
Training makes a dog well behaved and teaches it appropriate reactions to situations, it does not change a dogs character if a dog is put under enough pressure it will react at genetic level not the level it was trained to.
RIP Little man.