That’s how they play, play kinda rough! I’ve had plenty of clothes ripped, bites (accidental) while training. That said, if the attack WAS unprovoked (which we don’t know) then the dog meets the definition of a vicious dog.
If the guy was taunting the dog, in the dog’s face, we don’t know what went on, just that the dog got out, the guy got bit. It is pretty unusual for a trained dog to target anything except arms and legs. If I were a betting man, I’d bet the stomach, chest, groin were scratches, since from the picture the dog has a classic upper arm hold, often they will brace against your body with their front feet, rip the heck out of your clothes, that’s why you wear a scratch suit or Carhartt overalls. I realize the article says deep bites, but this is a journalist whose experience with protection dogs is about as deep as his experience with firearms, and we know what kind of idiotic references they make to various weapons.
The dog was drug inside while maintaining his grip on the upper arm, which is just as the training dictates. They don’t let go till the ‘out’ command is given, so I don’t believe he would bite in the stomach and let go. It’s not in their DNA or training.