I had a look on the GSD and Boxer clubs of America and they don't say anything about euthanizing or frowning upon white dogs
. They do include however that these dogs should not reproduce, so should be sold on limited registration. Personally I agree, I am not a fan of euthanizing due to faults.
Now...the Dalmatian Club of America, does explicitly say they expect deaf puppies to be euthanized. I happen to agree if you can't find proper placement (though I understand some breeders are working with rescue to place deaf puppies).
I'm completely fine with euthanizing puppies that are blind, missing limbs, or have other major health problems.