Violence or dog training?

The dog was beautiful. A black giant poodle (or at least looking like one) walking with an almost aristocratic air. Head straight and paws moving with a dignified attitude strangely out of place (This is a dog after all!). The owner, dressed with a red sweater with the brand name visible in the back, was holding the leach and walking toward me. The dog stopped to look or to smell something behind, its head even more erect.
The thug from the leach made it jump. It stops again and the owner, once again, gave a yank full of rage on the leach to make his dog follow him.
It was done with a vengeance, not a hint of compassion for the creature at the other end of the leach. I was so stunned by the violence of the gesture that I kept watching until they both passed behind me.
The man with the red sweater may be teaching his dog that he is in charge, but he is, in the process, revealing to everyone else in the street, the violence that inhabits him.