[Calico Cat]

I believe that the answer to your question is “context”. “Last House on the Left”—I’ve seen the original 1973 Wes Craven movie, unfortunately—was a horror film. A tasteless and bad one, certainly; and doubtless a certain percentage of its audience found its scenes of sexual violence arousing. Extreme Productions’ swill, however, is sold as pornography—literature or film intended specifically to arouse sexual lust. It’s the blatant marketing of rape, torture and murder as aphrodisiac that most people of conscience would find obscene and intolerable.

[Question_Assumptions]

I also doubt the performers in mainstream movies really get abused to the degree that the performers in more extreme forms of pornography do. What I find difficult to understand is why it's illegal to pay a man or woman to come to your home and have sex with you but apparently not illegal to pay a man or woman to come to your house and have sex with someone else while you film it. And if the boss in any other profession told their employees that if they didn't have sex on demand in front of others or they'd be fired and that sex was why they were hired, they'd be brought up on sexual harassment charges.