We shouldn't be prosecuting these people, but we should be figuring out how to get them help.
An adult person who is attracted to children can obviously not have any legal sexual contact with a child, just like anybody else, and so we need to make sure they have the tools and ability to get by without that.
I don't know what's best for these people. Maybe the best way to help them is to let them have this fake material. Maybe the best way to help them is to try to deny them this sort of material. There's probably some scientist out there who has studied what is the best thing.