We're all part of the same natural world, we have more in common than we have differences. The world we're all born into doesn't seem to particularly care about suffering -- it's baked into its very fabric, we're all going to suffer and die.

If you are going to survive, you have to kill every day, be it plant or animal; it's just the way it is. You can say that plants matter less than animals, and make up some justification about consciousness and suffering, but that is simply our own personal bias. There is no way to know if the universe cares more about thinking or non-thinking things, or if they share the exact same intrinsic value. All such moralizing is on very shaky ground and comes down to human bias and not much else.