Originally Posted by The Unfan

Because it in and of itself doesn't harm a non-consenting party. Providing a market for harm isn't the same thing as causing harm. Enjoying something, no matter how depraved it may be, isn't damaging. The rape is bad because the child is unconsenting. When you rape someone you deny them of their rights, you're impeding their freedom. That is why rape shouldn't be permissable. However, simply watching something doesn't take away any rights, and quite the opposite taking away someone's right to watch something impedes their freedoms.