My point is that, though everyone likes sex one way or another, not everyone likes every sex act or practice.
I don't believe for a second that as many people like BDSM as is represented in pornography. I also gave the example of urophilia which I think is overrepresented. Probably the same for anal: I know very few, not zero, but very few, straight women into anal, and yet it's very well represented in pornography. Same for same sex activities: lesbian tendencies seem to be a little under measured in the general population, but I definitely don't think that lesbianism is as prevalent as it is in pornography; neither are male homosexuality or transexualism. Or obvious age differences (there is a lot of old with young pornography, as in, an 18 yo with a 60 yo, all of straight, lesbian and gay). Or claims of incest: a lot of pornography is marketed as parents and children or as siblings, which it isn't (I know you're into incest, but again, how many people really are?) Even interracial, which she mentions, is probably overrepresented, likely due to the complexity of race relations in the USA. How many people really have a preference for interracial sex? I doubt as many as there is in pornography. Some fetishes require heavy specialization such as pregnancy and lactation. And then some fetishes are downright dangerous, such as smoking or obesity.
In all of those cases, and many more, my main claim is that, sure, maybe many performers are into what they do on camera; but definitely not all, and therefore some of it is catering to audiences for job reasons. All performance art does that in some way; but the thing is that porn isn't exempt of it as opposed to non porn acting, singing, dancing, or comedy.
Pornography and its sibling, prostitution, are real jobs. They may not require the skill level of neurosurgery, but they're still real jobs.
And although that was not the idea behind the thread, both are worse for the pornography performers and prostitutes when they're illegal. Because that makes them controlled by organized crime and prone to kidnapping, trafficking, and physical and sexual abuse. In the case of minors, this extends even to non pornographic modelling, as we know all too well...