Well we do allow adult porn stars. Doesn't your logic imply that we shouldn't, since maybe they were forced into it, and maybe they were even forced into it as a child?

What logic says someone can sell current pictures of themselves but not older pictures? Why worry about coercion in one and not the other?

If child porn is inherently bad, then it makes sense. That also explains why computer generated child porn was prohibited until the laws were mostly ruled unconstitutional. But if the only problem is the impact on the victim, then the victim should have control over whether they were really a victim.

(There are also consequentialist reasons mentioned in some of the rulings, though. For example, they say that child porn is used by predators to lure kids. Some of those reasons may have merit, and my "no victim" proposal may not work in reality all the time. But I feel it should at least be explicitly considered when deciding the law.)