I was kinda wondering if this topic would ever come up on here.
Hmm, there are unfortunately quite a lot of negatives associated with porn. Probably the biggest being the exploitation involved in the industry. I'd not super uncommon to hear about how former porn stars were exploited or drugged into performing, and there are quite a few who have either died from ODs, commited suicide, or just disappeared themselves.
From that perspective, it can be somewhat compared to the illegal narcotics industry, were, despite being legal, also tends to feature a lot of exploitation all throughout the supply chain, be it the poor farmers harvesting the ingredients, or the 8-year-old kids being forced to sell them to support their families or pay off debts.
That side of the whole industry probably doesn't have any effect or cause addiction itself, but it's almost structured as if to profit off of it in the same way.
Some of these issues are, of course, mitigated by amateur pornography. But again, not always. I'm sure most of you have heard about how a prominent porn site recently had to purge most of its amateur media due to accusations of hosting actual rape videos, child porn, revenge porn, and other non-consentual stuff.
Going back to profiting off of addiction though, I can definitely see porn having that effect. Honestly, one doesn't have to be addicted, or even experience an addicted person to see that something is amiss. There's so much other media, information, knowledge, etc. available on the internet, yet porn makes up most of the overall traffic anyway. Admittedly, I also tend to get drawn to the lewd stuff when I'm bored or have nothing else that I need to do. Perhaps it's not as bad as, say, a nicotine addiction, but there's definitely something there. I can tell, because I've been abstaining since this thread went up >///<
Hentai's a little different from the whole industry/exploitation side of things. Obviously, things depicted in hentai aren't real, so there's no risk of the actors/actresses involved actually being children or being raped. However, those involved behind the scenes: the artists, animators, voice actors, etc., might also be treated poorly, because they might have no other option.