The phrase "sick fuck" is also a socially acceptable way for people to reaffirm the limits of good taste and
normal behavior as defined by society. As with many
social interactions, there is an unspoken
subtext which is easily identified. People who are discussing someone who has been branded a sick fuck in the conversation are usually making mental notes about their own behavior, and may be gauging the distance between their own private actions with the actions of said sick fuck.
For example, two
straight men would probably not discuss their own
masturbation practices, but would readily offer commentary on someone else's masturbation rituals, real or imagined, especially if they could brand the subject of the discussion a sick fuck, thus drawing attention away from themselves.
Guy 1: "Hey, did you hear that Guy 3's girlfriend caught him
jacking off to the
Teletubbies?
Guy 2: "No way. I always knew that guy was a sick fuck."
Guy 1 rests assured, believing that his own practice of jacking off to Rosie O'Donnell is not as bad, since no puppetry is involved.
Guy 2 is not so sure of himself, since he has occasionally masturbated to Sesame Street and may actually enjoy stroking himself to the Teletubbies as well, but he must keep up the appearance of disapproval, or his status as a normal member of the group may be cast into doubt.