Over-diagnosed?
Sex and food are the only desire EVERYONE shares. We're wired to want them, so that we can keep ourselves alive and make new people. They are enjoyable because we're SUPPOSED to have and pursue those desires. It's just natural selection.
Granted, I'm asking having watched one episode of this show, where most of the people seem to be D-list celebrities just trying to reignite their lost careers...in other words, not REAL addiction.
I know that there definitely ARE real cases of sexual addiction, because it can disrupt your life and there is a real biochemical component to it. But I suspect that most diagnoses are more about a reprimand for not conforming to the unrealistically repressive norms of a puritanical society. If you have any lifestyle other than Christian, marital monogamy, SOMEONE will consider you a deviant. It's more about shame than addiction.