The case against victimless crimes

The Florida Supreme Court just upheld the child pornography convictions of a 16-year old and a 17-year old for having taken nude pictures of themselves and e-mailed them to their own e-mail accounts. The rationale appears to be that the pictures could have been sold to a third-party. Let's run with that idea- so, if you are 16 or 17, and you decide to snap photos of yourself nude and then sell them on the internet, you should be criminally liable??? What possible societal good could come of that? If our instincts about criminal responsibility are right, we don't think that people under 18 are as able to make correct choices as adults. If so, how does it make any sense to specifically impose criminal liability on under-age persons, and only under-age persons, for committing an offense that allegedly only harms themselves? This case shows the absurdity of victimless crime, and the unintended consequences of criminalizing such conduct.