But selfishness by definition is antithetical to empathy. This is the inherent contradiction in claiming that a selfish motive like moral or social vengeance is "pro-life". Vengeance, especially vengeance that seeks the deliberate extermination of a human life, is anything but "pro-life". It's all about forcing one's own concept of justice on the world through the deliberate destruction of other human beings. And I oppose capital punishment for that reason.
I do, however, have to acknowledge that being "pro-life" under all conditions and circumstances is unrealistic, and even irrational. Instances of self-defense are a case in point. Being "pro-life" when someone is set on murdering me or others is irrational because it doesn't work. It would result in more loss of life, rather than less.
So although I am "pro life", I have to recognize that practicality dictates that we will sometimes have to destroy life to preserve it. And this is why I say that one can be in favor of the killing of other human beings, under extreme circumstances, and still rightfully call themselves "pro-life".
I do not believe, however, that people who want to kill other human beings for the sake of moral or social vengeance can honestly claim they are "pro-life". For the reasons I posted above.