Explain why some people derive sexual gratification from the paraphilias when most people find these activities perverse, weird, and gross?
I don't believe that anyone can answer your question, since there are so many people afflicted and so many different types of paraphilia. Furthermore, it seems self-evident that many of the people who derive sexual gratification from the paraphilias keep their interests a deep, dark secret. Most of the psychological interest in the problems seems to be directed to identifying the different types and curing people of these aberrations, rather than exploring the possible causes. This can be seen in the eNotes material on the subject which can be accessed via the reference links below.