I agree OP they should be illegal. As should violent or degrading porn and a host of other perverted sexual products. But as long as they make a profit they will be sold, because thats how our society works isnt it? Anything goes as long as someone gets rich. It's all part of a trend suggesting all fantasies are ok, even those that are dark and dangerous, and can be acted upon. We can't police people's thoughts and fantasies but they are supposed to be just that, fantasies that do not happen in reality.
If someone has a fantasy about hurting a woman and is deeply ashamed of this because it is something that isn't acceptable in his society, he will keep it to himself. There is a small chance he will try to act it out someday but hooking up with women is difficult in this world and by the time he has a few dates and gets to know the woman the fantasy has faded for her. He is lucky and grateful to have a sexual relationship and the fantasy stays in his head. If someone has the same fantasy in a society that condones all fantasies, and he has access to 24/7 porn watching that fantasy be acted upon its going to normalise it and make it a tangible reality. Then he buys a product that allows him to act it out himself and enjoy the power it gives him. He can download an app on his phone where he can simply swipe when he sees a woman he would like to do this to, and he can arrange as many hook ups as he likes under a fake name where he can try to act these out. The women might say no but by then they've already consented to sex and are in a vulnerable space with him, so its easy to get away with it. There is no doubt in my mind that the man is the second scenario is more likely to harm women. We've created a perfect storm for sexual offences. That's the problem. This is just another layer of it.