This perspective may appear to provide a sense of empowerment through the subversion of one's pet peeves in their culture, but let me assure you this is not the case. The dilemma is, simply put, if all forms of expression are potentially equally as valid as any other, then how can we justify the examples set by individuals like Geoffery Dalmer or social experiments like Nazi Germany? While it may be true that as products of the imagination, Dalmer and Nazism are valid expressions of the human imagination, this cannot confer any real and lasting ethical or moral justification.
But, within the logic of the argument as so far presented, how can I justify denying moral sanction to an expression of the imagination? Simply because I make no pretensions to an autonomous, disconnected, purely mental-metaphysical notion of perception, apprehension, and thought. Every individual imagination is rooted in several things: one is his or her physical body, another is in his or her social-cultural relations (from images of family and family to experiences of the cosmos to cosmology; technologies both physical and metaphysical; artifacts and fantasy-histories), a third is in his or her specific physical experiences/location/climate/environment.
By being connected to all these things a person's or a culture's imagination is kept in check with reality, with the really-real. It is my belief that the physical informs the imagination and the imagination forms the physical - by merely pointing at a plant and calling it "plant" you have super-imposed an imagination onto that physical object; but you could not have called the plant a "plant," if you were not somehow 'connected' to it.
It is this connection to reality of both the physical and social worlds and bodies (Freud's very useful and suggestive idea of reality testing is operative here) that we find our way out of the dilemma presented earlier: how can we provide a social critique of human expressions/actions when we understand them all to be products of the imagination? Simply because we are tied intimately, necessarily to our bodies and worlds.
Our imaginations are subject to reality testing whether in the form of direct testing in the physical world ("Mommy, why can't I fly?") or in the social world ("She doesn't like me or does she?) As such all imaginings are subject to constant scrutiny by the morality-keepers in both traditional and contemporary society, ranging from the nosy, old-woman across the street to sanctioned, super-secrete policing-intelligence-thought-religion types. But this also happens on the individual level using unconscious, internalized censors which, if Freud is right, follow the dictates of social and cultural history.
In a less fascist-world, the optimal situation for judging, validating and justifying one imagination/discourse compared to another would be as follows: