I largely agree with this. The nature argument is fine when we talk about our drive to meet our basic needs (food, sleep, et cetera) but it falls apart when it is applied to more complex actions. I must admit I have misused it in this way at times, though.

I particularly like how this applies to the idea of subjective morality. If very little can be called part of our nature it implies that morality is not a thing that we are born with. I cover psychedelic use and the drug war and when I do my research I run into a lot of "moral" arguments from the anti-drug types and they all seem to fail to understand that their morality is not the only morality.

Anyway I will stop rambling at you. Good Post.