OK, Shot One, fair question. I can only answer based on my own first hand experience. Your tone comes across to me with a slight twist of bitterness so I can only assume your experiences were not like mine. I would add at this point that I am not a QFI, so I have no defence to make on this.
I can honestly say that in my many years of service I have never seen, or had reported me, anything that that would warrant being described as humiliation or physically striking a student.
I have been severely bollocked in a loud voice when my primary instructor at a secret Basic Flying Training base thought I was trying to kill him. But that wasn't humiliation even though he used harsh words.
I was once slapped for not warning an instructor before applying 8g to his body. But it wasn't any kind of physical abuse.
I have seen people, more recently, complain about being given a frank, honest, gloves off debrief. People don't like to be told bad things about their performance. I would agree that the totally straight approach to debriefing comes across as harsh to some people, especially some youngsters that have grown up in a fluffy environment where no one is allowed to experience failure. But sooner or later, the kids have to be told that "doing that will get you and others killed."