I have been around and raised dogs, specifically big dogs for about 30 years. Every time I’ve seen a dog turn, that’s every time with one exception, it was because of the handler/owner. The only exception to that was a dog that had a brain tumor and became very violent.
I’ve brought more than one dog back from abusive situations and it’s not difficult to do if you just have the patience and LISTEN to what the dog is trying to tell you.
I’m sorry but anyone that puts down a healthy dog needs an @ss whipping bad.
“it was because of the handler/owner.”
And sometimes that’s because of wimpy submissiveness by the owners. Unless you want to call that abuse. Which actually, I do. It certainly is neglect and denial of what the dog actually needs.