An interesting look at atheism in politics

So this post was inspired by something the Acupuncturist said to me at MightyMook's wedding, and I have been thinking about posting on it for quite some time. I actually have had thoughts in this direction for years, and I have articulated them in other situations, but I guess I have finally decided to commit the thoughts to writing.

Basically, since the Acupuncturist and I have similar views regarding spirituality and religious expression, even though we have starkly different political views, we have some commonalities - he was pointing out to me that one of the most irritating things about conversations with the extreme secular left was the tendency to completely dismiss religious sentiment and devoutly proclaim one's faith in atheism (heavy sarcasm intentional - atheism is a matter of faith just as much as belief is - agnosticism is more like a non-choice than anything else).

But here is the thing that I could never reconcile about the atheist left (and, I suppose, the atheist right, if there is one - I am sure there probably is, but they are simply mot prominent in the conservative movements) - why they seek to impose the morality they seek to impose.

First, they do seek to impose a morality - human dignity and compassion for the poor and the underrepresented are clearly moral stances. What I have never been able to figure out is why those are important to a true atheist. In a way I understand; if we are simply animals and have no higher "spiritual" calling, then we need a government to enforce that morality so that the law of the jungle does not reign. But therein lies the real problem - if we are just animals, why bother with that sense of morality at all. Why protect the underprivileged? What is "good" about that, and why even bother with the concept of "good" at all? Obviously, I don't believe this, these are questions I have for the atheist left.

Of course, "human dignity" is often raised, but nature does not recognize human dignity - that is a purely spiritual concept. A clever person might argue for the preservation of the "diversity" of our species using a combination of Darwinian theory and popular buzzword, but that idea fails, too, because why preserve the weak members of a species - what genetic imperative does that have? What is "good" and why should we strive to preserve your version of "good"?

Of course, one could always go the Nietzschean route and say that all the were trying to do was make their life a consistent artistic expression of helping the underprivileged, but that carries no more morally compelling weight than the consistent artistic expression of the predatory serial killer exploiting the weak for self-gratification. Since, under this philosophy, morality is superfluous, neither view is more right than the other. Nietzsche would still probably condemn the liberal more than the killer, because the liberal has bought into the "slave morality" of good and evil, while the killer is actually forging his own way, independent of any sense of right or wrong.

Not that I really believe anyone is reading this, but if anyone out there is, give me some insight into "Why?" from an atheist liberal perspective. I would understand it if it was from an agnostic perspective, and I think most people who make the claim of atheism actually fall into the agnostic category, because they cannot actually disentangle themselves from the constraints of the concepts of "good and evil" or "right and wrong" that are required for true atheist thought.

Help me out here.