[alex_anglin]

I would argue that it's a reasonable limit on whichever freedom may be cited not to allow the creation and distribution of child pornography, even when it is fictitious.

[somebodythere]

That limit is probably where real harm was caused to a real child.

[dTal]

It's not implausible that deepfake child porn ultimately causes harm to children. Allowing people to repeatedly indulge in a weak fetish may reinforce it into a strong one, or blunt a disgust response which would prevent them from acting it out.