1 and 2 apply to entertainment in general. There's something to be said for cutting back on TV, aimless internet browsing, etc., but it makes more sense to focus on cutting back total time than eliminating one particular form of entertainment in particular.
As for 3, I'm not familiar with that particular study, but in my experience studies of "porn addiction" or "sex addiction" tend to rely on dubious definitions of "addiction." I'd advise against taking worries of porn addiction any more seriously than worries of "internet addiction" or "social media addiction" or "TV addiction" or whatever.
I'd advise against taking worries of porn addiction any more seriously than worries of "internet addiction" or "social media addiction"
This sentence sounds like it's intended to communicate "porn addiction shouldn't be taken very seriously". But speaking as someone who is hardly ever capable of staying offline even for a day despite huge increases in well-being whenever he is successful at it, to say nothing about the countless of days ruined due to getting stuck on social media, these examples make it sound like you were saying that porn addiction was an immensely big risk that was worth taking very seriously indeed.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.