All life is killing. Even herbivores like deer, horses and cows will kill and eat birds, rabbits and mice. Most vertebrates depend upon, or are willing to eat other animals.

It's part of nature.

Even plants will eat animals if they get a chance. In fact, they could not live if animals didn't die on them, rot down into their roots, and return the phosphorous they need to grow and can't get elsewhere.

Killing and dying is not the worst thing. Disrupting the cycle of a biosphere by refusing to kill or die is the worst thing.