It was the Supreme Court that upheld a lower court's decision that the CPPA violated free speech - leading to the sort of porn featured in the documentary. But, of course, the real problem is world-wide societal demand.
If the real problem is the demand, reduce the demand. If you can figure out how to do that in a way that doesn't create worse problems.
For instance, a while back I pointed out that depopulating the Earth would definitely reduce the demand. If reducing the demand were your only priority, you would embrace that as a solution. But I gather, or at least I hope, that you don't.
You appear to be drunk on protecting such free speech; even when it leads to very, very bad outcomes.
Freedom is what someone else does that you don't like but you're not allowed to stop them.
Once you declare your own dislike should override the social systems by which freedoms are allocated and balanced, you've come out against not only that particular freedom, but all freedom everywhere. Your employer doesn't like that they have to pay you. The cops don't like that they can't search your home for evidence of illegal activity any time they feel like it. Your neighbors don't like having a person of your race or religion living there. The school board doesn't like that kids aren't forbidden by law to stay up late on school nights. Your doctor doesn't like that you're allowed to smoke or eat so much salty junk food. All of them can list enormous social harms resulting from those freedoms. Think of all the illegal drugs and missing children the police could find if they could just search whatever they wanted! Think of all the lives cut short that could have been saved if unhealthy diets were banned! Think of how much more goods and services would be affordable for everyone (except the slaves) if slavery were allowed! Think of all the immortal souls that could be saved from eternal damnation if practicing the right religion were mandatory!
If you want to avoid all the very, very bad outcomes of freedom, move to a Taliban country or North Korea. Though ironically, I don't think you'll find any less sexual exploitation of teenagers in those places.