If humans value life, what significance does another have for you?

If a woman is aborting a fetus or an embryo, or a person wishes to commit actual suicide, or a person in chronic pain or with a chronic disease wishes to end with euthanasia, or a person joins the service…many of these similar concepts in relation to the end of life; hence, what is it, most of the time, that keeps people wanting to see these humans do otherwise?

Does this make humans selfish or possibly egoistic? Does wanting someone to live for the sake of their potential mean that you would want to benefit from this potential? Thus, equating to an egoistic agenda or would the person be selfish simply wanting to look out for their best interest for the same reason?

The difference is selfishness does not treat self-interest as a foundation for morality, egoism does.

I asked these questions because I am having a hard time understanding why people are against abortion aside from religious reasons, as well as euthanasia, but meanwhile, no one is concerned that the air is unfit to breathe and the water is unfit to drink. Perhaps we will be purchasing oxygen in a can some day.