Why would someone murder college kids? Isn't that pointless? Why would someone propose marriage? Richard Dawkins’ assessment of human worth may be depressing, but why on atheism is he wrong when he says, “There is at bottom no design, no purpose, no evil, no good, nothing but pointless indifference...We are machines for propagating DNA...It is every living object’s sole reason for being?” 

In a world where there is no objective good or evil, emotions in the moment ultimately rule supreme: there is nothing beyond them, and so marriage is no better or worse than how it makes someone feel, which puts it at the level of a mass shooting. There could not even be such a thing as free will, because human "will" is an intangible concept that supersedes the level of chemical reactions in the brain. Saying that someone can "choose" to do something else in the moment is nonsense—they are a mere physical machine, using chemicals instead of cogs, but cogs turn with pointless indifference. 

Such confusion and such pointless indifference. There is no hope, only a desire for pleasure until death. 1 Cor 2:14 sums it up well, saying, "But the natural man does not accept the things of the Spirit of God; for they are foolishness to him, and he is not able to understand them, because spiritually they are discerned."