There are hidden contradictions in the minds of people who "love Nature" while deploring the "artificialities" with which "Man has spoiled 'Nature.'" The obvious contradiction lies in their choice of words, which imply that Man and his artifacts are not part of "Nature" -- but beavers and their dams are. But the contradictions go deeper than this prima-facie absurdity. In declaring his love for a beaver dam (erected by beavers for beavers' purposes) and his hatred for dams erected by men (for the purposes of men) the "naturist" reveals his hatred for his own race -- i.e., his own self hatred.
In the case of "Naturists" such self-hatred is understandable; they are such a sorry lot. But hatred is too strong an emotion to feel toward them; pity and contempt are the most they rate.
As for me, willy-nilly I am a man, not a beaver, and H. sapiens is the only race I have or can have. Fortunately for me, I like being part of a race made up of men and women -- it strikes me as a fine arrangement and perfectly "natural."
Robert Anson Heinlein
Excellent Heinlein passage. Thanks!