Robin,
I struggled with this too, and one of my teachers put it: “because we’re all one.” Consider that at our deepest levels, we know that life is magnificent. In a vast universe of noble gasses and many, many lifeless worlds, there is something special and beautiful happening here on earth. When we harm life we feel it in our core, a dissatisfaction arises, deep, primal, dissonance. When we encourage life, a spaciousness arises, light, buoyant, harmonious. Its great because its win-win. Respecting life produces better results for us, in that we are more content, joyous. As we grow content, then we respect life because it just makes sense. Like we would hug our crying daughter, or soothe our stubbed toe… naturally, warmly.
With warmth,
Matt