I had the misfortune of talking with a few potheads, and HN's reaction to porn addiction is the same of potheads, denialism, mental gymnastics, and everything but accepting that porn can actually be problematic.

The only reason it doesn't have it's own DSM classification is a mere question of technicality, whatever it is a separate and distinct kind of addiction, or just a manifestation of other types of hyper-sexual disorder.