Viewing porn is not naturally harmful to men or women. But I would offer some caveats. There are people who probably shouldn't view porn, like those with poor body image or those who have been sexually preyed on. Depending on your choice in viewing, you can develop unrealistic expectations about sex or what people like or how you'll be expected to "perform." And viewing with someone requires true permission.
When none of these red flags are up, pornography can certainly have benefits. Counselors sometimes suggest it to help people become comfortable with a particular fantasy they or their partner may have. Pornography can reboot a couple's sex life. It can give you ideas, or help you get in touch with what turns you on.
Pornography can reboot a couple's sex life. It can give you ideas, or help you connect with what turns you on. Pornography can provide you there at best, or disgust you at worst. All of it depends upon what you select to enjoy. With the accessibility of porn online, it's possible to sample sufficient porn quickly that you don't need to find yourself seeing wall-to-wall hard-core sex if it's plot driven erotica that interest you. You're just a victim of bad pornography if you let yourself be.
And a word about sex or porn addiction. I do not believe in it. Unlike a chemical compound, like opiates, you can't become "addicted" to sex or porn; you can become a compulsive audience. In this case, it's not the pornography that's the issue; it's the compulsive personality. If it weren't porn being used to act out one's compulsive nature, it might be food or some other behavior.
As for whether it's damaging or beneficial to the entertainers, let's take females initially. There are some who select to perform because they like sex a lot and they consider it a great method to earn money. Then there are those who are drawn to porn as a method of acting out subconscious mental problems-- looking for daddy's love or punishment for being a bad lady. For lots of, it's most likely a little of each. Even ladies with the best mental health will deal with some disadvantages from this work. Our culture takes in porn at record numbers, but the women who carry out are still evaluated harshly.
I'm not sure the male entertainers more info go out completely untouched either. While they might not be judged as harshly as the females, ultimately they're viewed as freaks who make their living with their anatomy. John Holmes's fate is the supreme cautionary tale.
Possibly if we weren't still so consumed with regret and pity about sex, neither viewing nor performing in these movies would bring the weight it does. But then, maybe we would not be so interested in them, either. If the fruit were not prohibited, would anybody care to take a bite?