This is a rather good thread on the pseudo-medicalization of psychological conditions that are often, in other instances, nothing more than perverse sexual fetishes and I recommend it to you. One of the interesting aspects here is the status of perversion under liberalism. To put it bluntly, liberalism not only lacks the philosophical and moral framework and vocabulary to distinguish and elaborate the perverse from the good/ natural, it is actually and increasingly hostile to any such architecture and vocabulary.
The framework and vocabulary that distinguishes and elaborates the perverse from the good/natural is one that is able to identify what certain things are as well as what they are for. The problem for liberalism is that it abandoned this framework from its inception and overtime the remnant vocabulary was purged as it ceased to make any sense within the framework of liberalism. Now, whenever we are confronted with what was formerly understood as perverse conduct, within the framework of liberalism, only the ideas of consent and harm are our guides. While these ideas are serviceable within their limited range, as guides they in no way exhaust the legal or the moral, and they certainly provide no assistance in identifying or dealing with perversity.
And it’s precisely because of this absence and hostility that our understanding of perversity follows a pattern of first being psychologized, medicalized, and finally normalized via a program of de-stigmatization. We now see the reverse occurring; that is, people that maintain an understanding of this or that conduct as perverse are, firstly, stigmatized as extremists, bigots, and the like, and, finally, psychologized as suffering from irrational fear (homo/ trans/ –phobia). Many such cases, indeed.