Surely part of the answer is that the values we inherit from our social environment do not fit together into a coherent, consistent whole, but conflict with one another.
On the nature question, I have no problem accepting that there are biological and physical aspects of human life and its environment that social development cannot change, but it's a mistake to think of them as an organic whole called 'nature', which we could therefore be somehow 'in' or 'out of touch' with. The aspects become more or less important and are assembled and interpreted in different ways as society changes, and by different groups within society.
Mike