Life cannot exist without excrement, but relatively few people think highly of poop. What is your point? If you go far enough with your reasoning you have to basically value the entire universe and everything in it to be allowed to say you value any particular thing. It dilutes the meaning of valuing something to the point where the word/concept itself becomes meaningless.
I disagree. You cannot hold this principle "in theory" without understanding the specifics of this case.
It makes no sense to value (human) empathy and cooperation without valuing (human) life. You can argue about first principles, excrement and the universe, but this will still be true.
Without valuing human life, all sorts of things start to unravel in our society. Of course, just life is not enough! Empathy, cooperation, kindness, curiosity, etc: all things that make the human experience worthy.
I don't disagree. It is valuable because of all those things, and more. It is not valuable at all costs. But human life is the sine qua non (for now, without going into scifi territory).
I would argue that someone in permanent vegetative state is not much of a "human", mind you.