Yea the one reason I'm against flat out legalization of every drug (only wanting decriminalization) is because people who shouldn't have access to the drug would have significantly easier access to the drug (just having someone buy it for them). Primarily kids, since they practically constantly do that with cigarettes and alcohol and have started especially doing it recently with vapes and weed as weed has become less and less banned. I'm pretty confident a majority of high schoolers vape and that's because they're very easy to legally get and therefore they usually have someone buy them for them, and also a lot just get sold vapes by the vendors anyways and neither the vendor nor the buyer really stand a chance of getting caught just because of how little you can do to actually control that (without relying on a bunch of kids just going and telling cops "this place sold us vapes")

Kids obviously aren't immune to doing crack or heroin now but if it were just legalized it'd make sense that the amount of them abusing it illegally would become wayyyy higher. And that really IS a (big) problem, unlike shit like books that don't follow a certain agenda or drag queen story hour. It could screw up a large portion of the population for their young life. Best you could do to prevent such effects is teach how to be safe with drugs and how to prevent/reduce certain bad things from happening (already good idea anyways), and to implement draconian (and expensive & time/resource consuming) measures that would make monitoring all the children & drug stores extremely closely at almost all times a possibility so you could nip the bud of any absurdities like adults giving/selling drugs to students early on.

I see just decriminalization as not much of a risk because you aren't basically enabling businesses everywhere to (legally) sell these drugs, which would generally make it more accessible to kids, you're just making it so doing drugs won't get you fucked by the authorities and destroy your life in an unnecessary way through prison "rehabilitation" (slavery aimed not to rehabilitate but just to make money off the prisoners with little regard for their rehabilitation or their life), or just getting shot/falsely arrested by cops, or maybe stopping false searches too.