In times or places where this abundance is not as shockingly unnatural, the feeling of the food we consume takes less importance. And, as others said, it's not just animal. Killing a plant, often in way more atrocious manners, is just as bad.

We'll probably have to murder and massacre our food for a bit longer. Live with it and work on synthetic food, this will resolve the problem you have with life-sourced food. Well except we'll probably still have to kill millions of animal and plants for population control. Heh.

You know we also kill, without asking their opinion or respecting them much, other more exotic life-forms, like virii or bacterias, that are as innocent as the rabbit you had in your last civet. All they did was follow their instincts, and they didn't have a choice contaminating you; but you had a choice killing them.