Nothing wrong with protection training, per se. It’s just the fact that to stand the training, breeders strive for traits that can go too far. Many dogs that take the training are good, solid dogs. The problem is when they have siblings who are TOO “hard”. They still end up in the gene pool because the breeders think they have good traits or don’t see the bad until too late - puppies long since were produced.
Not shocking the dog likes females, especially when raised by 1. Happened with my sister’s male GS each time. Except they loved our male close family - our dad, my husband, etc.
My own females...well, the current doesn’t count. She loves EVERYone. My most wonderful dog prior, was very much attached to me, female. But I don’t think she showed preference for either amongst strangers. Had a pup who wasn’t around long enough to know. My first ever did not seem to care, either. Maybe females treat everyone with equanimity.
That could be very true.