Maybe 1 and 2 apply to entertainment in general, but I think there are a few things that make porn different:
I suspect porn is in some way "more" of a superstimulus than most other forms of entertainment. At least for me, it seems to tap into a more visceral response. I don't know of any research about this, but that doesn't mean I should ignore that intuition.
Many other forms of entertainment have plausible other benefits (albeit often minor). Reading fiction could plausibly improve your language ability and empathy. Gaming often has a social component or a skill-building component (even if that skill doesn't transfer to anything else or only transfers to other games). TV and movies may have some similar benefits to reading. All of them have the advantage of giving you topics to discuss with other people, whereas socially discussing the last porn you watched is usually not a good idea.
In addition, "quit porn" may be an easier rule to follow than "cut back on superstimuli (but don't quit any of them entirely)."
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.