Well, for starters, that section was the adolescent dog section.
From my limited research, the general consensus was dogs are no longer puppies at around 1 year old. It can vary but that’s the most general age I found.
“How Long Do Puppies Grow? Although all puppies are officially considered adult dogs once they reach one year old, puppies continue to grow in height and size while their bones are still developing, which takes anywhere from 6 to 24 months.”
At any rate, it’s a silly argument. The only reason he used puppy was to make her look as bad as possible.