good breeders and breeders other than GSD breeders do it
all of the time. all of that pushy, high drive, independent
dog stuff is controlled by training and socializing to a large
part. a dog at 8 weeks old isn't the same dog at 2, 3, 4, 6
months old.
a dog from a long line of Schutzhund titled dogs is going to turn into
a reactive, aggressive out of control dog because it's in a pet home.
i have an imported dog from a long line of Schutzhund titled dogs,
dogs that are shown internationally. my dog is a pet/companion.
the reason i bought a dog from such a line is because i knew
if he could do Schutzhund he'll be easy to train and socialize
for anything.
the people that bred the OP's dog sound like byb's and some
breedings can be bad.
I don't think any good breeder should give any customer "pick of the litter." A dog should be matched to an owner based on what the owner will be doing with the dog and their experience level.
An extremely pushy, high drive, independant dog will be great for the person wanting to do SchH at a national level but could turn into a reactive, aggressive, out of control dog in a "pet home."
And I see no indication that this breeding was thought out. Some bloodlines mixed with one another do not mix well and bring out nothing but bad traits if bred.