Because it involves changing people's values and ideas, and building a politics around those cultural conceptions. Whether what we protect is deep wilderness or an inner-city community garden, from a cultural point of view what we are protecting is a symbol of what nature means to us. This doesn't mean that places are only symbols or pure cultural constructions. The world exists, and yet we experience it through our own ideas. Our politics in particular are built out of those words, ideas, symbols.