Not true at all. I've owned 3 GSD's and they were all dog friendly and loved other dogs . Sounds like an excuse to me. I'd try him with one dog, very social, in the walk area and see how he does and take it from there. They're being very unfair to this guy and need to wake up. He won't be adoptable if he isn't social. My girlfriend has a GSD and brings her to play with my Labs on a regular basis. Someone at your shelter needs to wake up!
Labmomma