But then again, this shelter treats it's dogs better than a lot of owners. They get walked twice a day for at least 15 minutes, they get played with, trained, and generally socialized. For a lot of dogs this is more activity than they've ever had.
In my opinion, while there are some dogs out there with bad temperaments, GSDs included, most of bad dog behavior comes from poor management or breed choice. German Shepherds are not going to be your best friend when they meet you, you have to work for their loyalty. But once you have it, they will be the most loyal dog you've ever had.
They're smart. If you don't give them a job and set rules, they will create their own job. And that job will most likely be something destructive. These are not dogs that can be thrown in the backyard while you're at work, be walked once a day and call it good. Basically, they are not the dog for the "average" pet owner. But this may be a bit cocky, but I don't think that any of us on this board are the "average" pet owner. We know how to train our animals, we know how to troubleshoot problems, and we know when we are over our heads and need to seek outside assistance.
The issues I see with GSDs are not behavioral, they're medical and societal. As previously mentioned, this breed has some severe medical issues. The only way to avoid most of these is to do your research and get a puppy from a very respectable breeder. If you're rescuing, it's a bit of a crapshoot. Also, GSDs are on nearly all breed restriction lists for apartments, and are on a lot of housing insurance lists as well. Definitely double check your policy.