I made a german sheppard too aggessive; understandable or reprehensible?

I bought an expensive female black with white marks belgian german sheppard which grew to 110 lbs in a year and half. Before this one, I had a german shppard-collie that lived to be 16 yrs old, so I thought I knew about german sheppards. I raised this female belgian to be too aggresive, hair went up on its back when it met someone new, it was unbelievably aggressive and it was apparant I raised a ticking time bomb. Proffesional trainers for state police dogs took the dog in for one day and said mine wanted to attack a 135 pound state trooper dog which would not fight back because it would only fight back if commanded . They actually tried to have the dogs sleep in the same room but it was impossible. They wanted my dog to become submissive to the larger smarter sheppard but it would not, they said.said it was beyond them. Other experienced dog trainers were horrified by this dog. I lost my home, couldnt find a home for it and had to put it down. Is it possible the breeding wasnt right ? Or was activity like putting on old flannel shirts for her to tear apart that much of a mistake ?