Then there is no morality except spreading your genes as widely as possible and destroying any competition, through any means necessary.
Exactly. The Ten Commandments and the entire Western Civilization founded upon Judeo-Christian values are out the window. We're all just evolved monkeys that only "think" we know better.
It is more complicated than that. Man evolved to function in groups, for the purpose of outcompeting other individuals, and other groups. (Not group selection, but selection for individuals who spontaneously formed effective groups.)
As a result, man eolved selflessness, honor, loyalty, and charity to their ingroup. Even monogamy and two parent child rearign are strategies to enhance the competitiveness of those who compose the group. All of these loyal urges developed to aid the group in competition.
Of course, there is an alternative strategy which envovles promiscuity, dishonesty, and selfishness, and that is Liberalism.
You see both strategies throughout nature, beginning with r/K selection theory.
God did create the world, and He does intervene periodically (I know. At 22 I was an agnostic mechanist, who saw the universe as a God-less clockwork mechanism. I didn't come to believe easily.), but He also imbued it with a mechanism by which goodness would be rewarded in perpetuity, and would be able to outcompete evil.
The irony is evolutionary theory is amazingly supportive of Conservatism. If you explain to a Liberal how their ideology mirrors the r-selected evolutionary psychology, and how Conservatism mirrors the K-selected psychology, they are crestfallen, and ashamed, in a way many Conservatives could never imagine being.
If we learn to use the weapons of our enemies, we can easily destroy them. Whether we will or not, remains to be seen.