If we simply want to try to force better behavior by writing laws, we can do that. But if we want people to change their behavior and decision making towards other species, they need to understand the rights of other species as an expression of a fuller understanding of the underlying principles behind the concepts of human rights.
I feel that even if people were to understand the rights of other species. People would still ignore them for personal gain, similar to how even some people ignore basic human rights of others for their own gain.