Even if it's simulated, some things are wrong, and shouldn't be transmitted in a free society.
If I make propaganda that depicts a minority as debased animals who need to be killed, I shouldn't be allowed broadcast or distribute it.
Likewise, if I make something which, while produced without breaking laws, functions as propaganda for rape, incest, paedophilia, bestiality, I don't believe I should be allowed transmit that.
There's a lot of porn, which wouldn't be considered extreme by some standards, where what starts out as a rape attack on a woman turns into a sexual experience she enjoys. There is a strong case against the distribution of this material, based on interviews with convicted rapists. In studies of the sexual disposition of rapists, the above fantasy is the most common.
That's not to say that a video makes a person a rapist. They need to have something else wrong with them first. I however, lack the necessary expertise to say one way or the other if simulated rape porn makes a person with the ability to rape somebody more or less likely to do so.
This is one basis for which I would always have a fallback for stopping people distributing stuff, in extreme circumstances.
Most of us live in countries where materials which constitute an incitement to hatred are banned.
I don't see how anybody would have a problem with similar restricti.ons on media which incite attacks on the individual