Child porn prohibition is not about consumers. It is about increasing the risk on (and taking the market away from) producers, who are necessarily actually abus

Child porn prohibition is not about consumers. It is about increasing the risk on (and taking the market away from) producers, who are necessarily actually abusing real children (who are not the producers themselves) in the real world in an unambiguously horrific way, with the end result that less child abuse happens. You will have to try pretty hard to spin that into being the same thing as drug prohibition. Arguments are, of course, less strong for convicting 16/17-year-olds of child porn for sexting, and even for removing images that were produced long ago.