A "naturalistic" value system wherein life is held in little regard on the basis of nature, itself, not valuing lifeWhy not? If your values are not in line with nature then you are simply borrowing from Christian culture which you despise. How are your values different from american culture? You can say that they are not but some other atheist may decide to take you apart for everything you have and he would be complying with nature and would not be wrong in a godless culture. You would have a lot in common with him because both of you do not fear God. Besides your obvious anger issues say otherwise about your so called values.
We can even say the reason he took from you everything you had. including wife and kids, hauled them off into slavery had not one thing to do with His atheism because atheism is simply a lack of belief and it takes positive belief in something to do these things.
Your sense of right and wrong comes with consequences in Godless nature. There is a natural penalty to pay when one walks around with fictions in their head about alleged right and wrongs. There are two types of animals in nature. Wolves and sheep. You sound like the latter.
Your moral parasitism is not to be confused with your alleged claims to an independent moral system. It is simply adapting to the cultural system already in play, largely based on Christian principals that have not been stomped out yet.
Interesting discussion all the way around, tree. You sound like a decent guy in spite of it all.
These are the only two choices, huh?
Might want to rethink your position...