Prohibition is at least part of the problem. Since LSD isn't something anyone with a prescription can wander down to CVS/Walgreens and pick up a known quantity, how much LSD is in a given dose is a mystery until after empirical testing. Imagine if a can of alcohol had an unknown effect until an hour or two after drinking it, with effects ranging from a mild buzz, to being black-out drunk, to alcohol poisoning resulting in hospitalization or death. Every regulatory body would be similarly hesitant to allow it as the situation mentioned here.