Rights are inevitable because as our society advances, we grow insulated to the natural world. We arrive at the top of the food chain, and so the only direction we can kill for gain is horizontally, in other words, each other. As this practice progresses itself, we grow disgusted of it while we are simultaneously becoming sensitive and soft thanks to the comforts of advanced society. We desire stability, we apply the golden rule of ethics and establish universal rights.
I find the concept of rights so beautiful, I apply them retrogressively to other forms of life, since I apply human standards of conscious to everything to compensate for our ignorance of their subjective experience. Human beings supposedly have the most exquisitely sensitive of consciousness, so it would seem safe enough to judge on this criteria.
I still experience cognitive dissonance when I eat meat, though I'm not yet ready to come off of it. I just hope we eventually find a way to divorce ourselves from the practice. However, even trees have shown to exhibit stress signals when others are cut down in their proximity. What is pain and fear and is it relative? This experience can be traced to the original life form. Where to draw the line? Why not curl up in a ball and die, lest we step on another weed that shrieks in pain and sorrow in its own way. For all the physical comforts we enjoy as a civilized society, I think the intellectual experience has become proportionately more arduous.
Schopenhauer once made a statement about the proportion of good to evil in the world. He was a pessimistic philosopher, though he called himself a realist. Thus his opinion was something along the lines of this: Just compare the relative feelings of an animal enjoying another animal as a meal, and the feelings of the animal being devoured.
For fear of becoming paralyzed before the horrors of the natural world, I tell myself that steak is absolutely delicious. And it truly is. The best we can do now is make slaughterhouses more humane, if that's possible, with quicker, painless deaths. Until we can wean ourselves off of meat altogether. As we advance, this option is more than possible. And it is better for everyone involved, including the environment.