I'm talking completely out of my ass here, but I feel like excessive masturbation — whatever we might define "excess" to be in practice — is often related to alienation and just terminal boredom. Which is to say, if you feel like you have no control over your own life, and no impact on anything around yourself, then you still have control over your own body, and your own impact on yourself, right? You crave stimulation, and you can give that to yourself — lo, how independent you are!

The pathology would then arise when, essentially, the signifier is conflated for the signified: when the frequent masturbation being a result of lack of control over one's own life, is reinterpreted as frequent masturbation being in itself lack of control over one's own life. This, I'd reckon, would generally occur when someone on some level does not wish to acknowledge that thon lacks control over sy own life, and therefore chooses to hate whatever represents that lack of control rather than confront the fact head-on. Alternatively, someone could've just internalized those ridiculous ideas of any amount of masturbation being harmful. In many cases, well, both.

In any case, when you believe yourself to not be in control of your own masturbation, and masturbation happens to be your coping mechanism for your lack of life control, then these will obviously only feed into each other in a very unproductive way. Badabing badaboom, you have a "porn addiction".

Now as I'm saying, I'm just talking out of my ass here, but I do feel like this would explain the general leanings of supposed "porn addiction" with regard to gender and political ideology. Because if you're the gender who's raised to feel like you're owed the world, that you should be on top and in control, then you're more likely to have a pathological reaction to not being that; and if you're the type who would project your hatred of the contradictions of capitalism onto its pool of imported labor, then you're more likely to project your hatred of your life being kinda shit, onto your own genitals. Yet the actual mechanism of "porn addiction" would be, strictly speaking, neutral in terms of gender and ideology — it would find itself anywhere profound boredom would cross paths with a lack of life control that a person for any reason just could not face...

...Except, what about ideas like supernormality and the hedonic treadmill? Why do some people meet their "porn addiction" with shame while others "embrace it"? I can't account for any of that, so I don't think I have all the answers.