Since we can't ask the dog if he likes being kicked, I guess we'll never know if he considers it to be a "game", will we???.
And, yes, my dog likes to play tug-of-war, too. My dog is a Shiba Inu, not sure where they stand on the intelligence scale of dogs, but all I have to say is "give it" and she lets go of the tug toy! Geesh! I had never trained a dog before this, so I guess it can't be all that difficult.
Maybe you're a better trainer or your dog is smarter. Who knows? Maybe the guy made the mistake of playing tug of war too often with his dog and the dog thought it was always a game. That's the trainer's fault. But we are talking about a working dog here, one that needs to follow rules and obey ALL the time and not just when he feels like it.
Now I agree that if he had it strung up by his neck and was kicking it for no good reason (as the story tries strongly to imply) than it's horrible. But if he's trying to make it let go of it's leash out of it's mouth and the dog doesn't take him seriously than I can understand his tactics .