The beauty of this logic is that the wrongness of something falls into what we define by "cruel" which fits better into our actual moral arguments and lets room for changes in opinion without changing all the logic.
For instance for a person to move from not being vegan into being began only would need to consider that eating meat without need is indeed cruel, and then wrong. But the whole structure of trying to avoid cruelty stands.
I find it more "elegant" that a moral solution that tries to give animal rights, because then you would need to move into big changes in logic to move from one position to another.