I have a pet hypothesis that, on average, those into step porn are more likely not have grown up with a sibling of the gender they fancy. I reckon those of us who did are more likely to repelled by anything alluding to incest.
People who grew up with ACTUAL hot step siblings notwithstanding.
Ohhh. I forgot i had posted this before. You asked the same then and I don’t know what it means. Maybe that’s something from their childhood? Do you know them? Maybe sibling fuckers are more common than i realized.