I found this article, and the questions he poses at the end, relevant:
http://opinionator.blogs.nytimes.com/2016/01/04/between-past-and-future/?_r=1
I had also considered posting that piece here when I read it. Its relevance becomes even more direct when you extend the author's reasoning beyond the question of making sacrifices while we're alive (which is what he examines) to the question of making sacrifices (if you can even still call them sacrifices) once we're dead (which is the true topic at hand).
The author argues that if, in a thought experiment where it were somehow possible to do so, we would (or would at least recognize that we
should) be willing to sacrifice ourselves from ever having come into existence in order to prevent past atrocities from ever having occurred, then, in the reality in which we actually find ourselves, we should be willing to sacrifice at least something of value in order to prevent or mitigate present and future atrocities.
In making this argument, he notes the following caveat:
I should note here that the situation of the past is not exactly symmetrical to that of the future. There is a complication. If I had not existed, I would not technically have lost anything, because there would have been no “I” to lose it in the first place. (Of course, it’s even more complicated than that. I have to exist to consider the possibility of my never having existed.) However, now that I do exist, in sacrificing myself I do stand to lose something — my future existence.
But this caveat no longer applies, or at least applies to a lesser extent, in the context of decisions that won't take effect until after our own death, when we will once again not exist. So the situation of the post-death future, once we cease to exist, is closer to being symmetrical to that of the past, before we had ever come into existence. (It's still not
perfectly symmetrical, I think, because now that we do exist, we are aware of, and we care about, things that we expect to survive the termination of our own existence, which would not have been true had we never existed in the first place.)
This is all just another way of articulating Rebs' "low-hanging fruit" concept, I think.