Cue Kevin Tillman: "He's not with god; he's ..."
Yet that rarely stops anyone from pursuing purpose or meaning, and for the ambitious, a legacy of any sort is the closest they'll ever be to reaching immortality, or relevance beyond their immediate sphere of influence. If you're purposeless, why shouldn't your decisions echo throughout history, and make you moderately less so on a less cosmic scale?
Nihilism is an outgrowth of atheistic convictions, when adopted without a supplemental normative framemework that prescribes and justifies a system of values, or when adopted by the depressed or otherwise mentally ailing.
I've seen no coherent argument that life should be considered sacred in the face of a universe devoid of meaning or purpose, whether one's own or that of others. The concept is hardly a cure for nihilism. Offering it as a more legitimate alternative simply because it's more comfortable or reassuring to many people occupying a nihilistic space.
I should also mention that this guy, with everything taken from him, made to feel completely insignificant, was able to save maybe a few lives, and he'll never know about it.
In ten years, given the rate of social change, everything I do today will likely be considered outmoded, backwards and probably contemptible.
In our increasingly atheistic society, even if I have a negative impact on history, I will likely be unpunished.
If I wanted to make myself a legacy, and had suicidal tendencies, the shortest path into the history books is clearly a destructive one.