This documentary does hit on the key issues of instinctual drive, Sex and Aggression. I felt like sex and aggression was met by both participants in each sexcapade by the use of what the customer felt was a mixture of love and domination. Love is what I felt all the customers were looking to their dominatrix for; and by them humiliating, beating and subduing them the customer attained a feeling of what they felt was love, something that had probably been lacking since early childhood. Aggression for the most part was released by the mistress who, in my opinion, also needed that release of a basic instinctual drive -- Aggression. This was probably fueled by a subdued hatred for men or to attain that feeling of power one gets when they conquer something.
Another issue is the cathartic effect this type of expression has as a means for deterring non-consensual sexual activity. This statement was illustrated best by the man who had psychotic thoughts and feelings and used this as a means of "getting things in his head right", if he had not had this mental and sexual release he could very well have committed some sort of heinous crime against humanity. So I may not agree with these people or even see the soothing capabilities of this "therapy" but that does not mean it does not hold its own social value and merit.
In closing I would like to say that I feel enlightened to have this information, which may help me in the future to sympathize with someone who may have that "urge", and I feel that armed with this knowledge I may be able to recognize that deviant in the future.