That advice regarding cows is to protect the human's life, not so the dog can escape the cows that have been freaked out by the dog.
By releasing the dog, the owner ceased to have any control over it. The dog then abandoned the owner, who had zero visibility it control over the dog. Anything that happened after that is pure luck.
The agitated dog could have flipped out and savaged a child and the owner wouldn't have been there to intervene.
No matter how you dress this up, it is not responsible for handling or ownership.
As per the original point, if that dog had been picked up and found to be unchipped, it should have been destroyed as a deterrent to all the idiots, such as the owners of those other dogs, that let them roam freely.
That sort of punishment if the only way to get the irresponsible owners to engage with any sort of compulsory licencing.