The Dogged One was no saint. He pursued the scum of the world for selfish reasons instead of contributing to society. He wanted revenge, plain and simple. Exacting justice was only a side effect of his endless pursuit to kill every murderer.
Ves put it this way. "Even victims are marked by the darkness in their hearts. Some find a healthy means of coping with their trauma. The Dogged One can only sate his thirst by inflicting the same torment to those who resembled his tormentors."
In a dog-eat-dog world, refined notions of justice had no place.
In fact, Ves mirrored the Dogged One's tendency to seek revenge to Dr. Kawasaki's urge to see others suffer from his inventions.
Such was human nature, no matter much others liked to argue otherwise. In fact, many aliens exhibited the same tendency, but that was another story.
"Am I going astray?"
He originally planned to design a training mech. Coloring his design with an intensive myth like the Dogged One might be counterproductive.