I’m not an expert but I have spent a little time doing Schutzhund training including bite work. I seriously considered going into this more deeply as a “helper” or decoy (really the bit trainer) but my dog’s tenperament wasn’t into it.
Training methods are all over the place and I agree that some are quite distasteful - I wasn’t willing to do certain things in pursuit of an arbitrary training objective that wasn’t even a good match for my dog’s breed.
I could see that you could get a dog to pass training standards and not have a stable or trustworthy dog. I could also soo that not everyone is equally qualified to handle certain dogs, especially if you don’t know the methods used to train them.